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seasoning cast iron: contradictory methods, and which is best?

i love cooking in and maintaining my housemates' cast irons. so when i moved to my new apartment, i bought a new lodge pan and a bunch of old nasty rusty mysterious-goo-covered ones off of craigslist that someone had been using as country kitsch wall decoration. i want to clean and season them properly, but the methods i've found online contradict each other wildly -- some say to clean the crud off with soap, others forbid any soap even for the initial cleaning. some recommend steel wool, others frown on it. vinegar soaks? baking the rust and goo off? what to do? some seasoning methods require a lot of oil at very high heat, others a tiny bit at 200 degrees. the times vary too.

so, do all of these particulars of temperature, heating time, and cleaning method actually affect the pan, or would basically any combination of scrubbing, oil, and heat do the trick? what do you all swear by?

thanks, you guys!

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  1. Most of the folks I've seen season cast iron overheat the pans and that's not a good thing.
    If I procure a pan, grill, etc. that has been abused I first make certain that all of the rust, corrosion etc. is thoroughly cleaned off. Whatever it takes to clean the iron (steel wood, sand paper, even sand blasting or bead blasting of the pan is worth the expense) is what I use. NEVER use chemical cleaners.
    Of all the resources on care and use of cast iron I've read, this site is (IMO) the best single source for the type of information you're looking for. It focuses primarily on dutch ovens but all the principals that apply to cast iron dutch ovens apply equally to the care and feeding of any cast iron cookware.

    http://papadutch.home.comcast.net/~pa...

    1 Reply
    1. re: todao

      thanks, todao! that site looks good.

    2. On America's Test Kitchen, Chris Kimball cleaned a rusty cast iron pan with table salt and enough water to form a paste, using a wad of aluminum foil to scour it with, and plenty of elbow grease. I've successfully done the same. You then rinse in hot water, dry well, and rub with oil. Do the oil after every use until the food releases easily.

      8 Replies
      1. re: greygarious

        Are you sure he used water and salt? I thought it was oil and kosher salt and then paper towels to scrub while it was heating on a burner. Anyway, that's how I did it. I bought a Lodge 12" cast iron skillet with the helper handle for $6 at a flea market. It was quite rusty so I used the side burner on the gas grill (just in case it got messy, I wanted to do this outdoors) put some oil and salt in the pan and used a steel wool pad and then a bunch of paper towels to scrub it. I used quite a few paper towels. I just tossed them in the grass and kept scrubbing until the rust was gone and it was all oiled up. Then I left it on the burner to get quite hot and a little more oil. The best thing for the pan now is to use it a lot.

        1. re: John E.

          Rust reacts with aluminum in the presence of a reactive chemical like chlorine in salt. The aluminum pulls the oxygen molecules from the rust, leaving iron powder and aluminum oxide.
          Check out the thermite reaction: http://en.wikipedia.org/wiki/Thermite

          Personally, I prefer a drill and a sanding disk, as it makes the surface smoother, plus I'm a lazy son of a gun, but that's just me.

          1. re: ThreeGigs

            I seem to be missing something. Where does the aluminum come from? Cast iron rusts, aluminum doesn't rust (although it has other chemical reactions to boiling water and acids).

            1. re: John E.

              I think the aluminum part come from greygarious's suggestion of using a piece of aluminum foil.

              1. re: Chemicalkinetics

                I must have stopped reading after he said water. I don't remember Kimball using aluminum foil. I thought it was a wad of paper towel scrubbing with salt and oil.

                1. re: John E.

                  JohnE,

                  I use your method for cleaning. Oil with salt with paper towel. I don't know what Kimball uses. There are many workable methods. People have used cast iron for thousands of years in many parts of the world. I am sure there are hundreds of functional methods of taking care of cast iron cookware.

                  1. re: John E.

                    Doesn't the paper towel shred really quickly?

                    1. re: EWSflash

                      I had steel wool under the paper towel doing the scrubbing work. The paper towel was mostly there to protect my fingers from the hot oil.

        2. ramonasaur: "so, do all of these particulars of temperature, heating time, and cleaning method actually affect the pan, or would basically any combination of scrubbing, oil, and heat do the trick? what do you all swear by?"

          Everything that you need to know, in detail:

          http://chowhound.chow.com/topics/4768...

          As extended and emended:

          http://chowhound.chow.com/topics/6699...

          Accept nothing that contradicts the advice in those two links.

          2 Replies
          1. re: Politeness

            Wow, seems I have a cast-iron legacy :-) Thanks!

            1. re: ThreeGigs

              ThreeGigs: "Wow, seems I have a cast-iron legacy"

              That's because -- as Carly Simon crooned:
              http://www.songfacts.com/detail.php?i...

          2. "some say to clean the crud off with soap, others forbid any soap even for the initial cleaning"

            If your pan is perfectly fine, then you don't need detergent to clean it because you want to perserve as much seasoning surface as you can. However, if it full of rust and crud, then clean them off with whatever is necessary. At that point, if you have to scarp off some seasoning along with the curd, then so be it. It is about prioritization.

            I agree with most of methods mentioned here. There simply isn't a single workable method. To remove rust, I would try to first use water and detergent to clean, wipe dry, then start to use paper towel, oil and salt to do the real rust removal. The salt acts as an abrasive, the oil acts both as an lubriant and prevent future rusting, paper towel is just easy for throwing it away. I make sure oil is the last thing the cast iron cookware see and not water. If you finish cleaning the cookware with water, then it will likely form a thin layer of rust no matter how careful you are.

            1. It's just 3 steps. 1: Get the pan down to the bare metal. 2: put on a light coat of oil. 3: bake for an hour at 400 degrees or so.

              Ok, details, details, details.
              1: Bare metal. How you get it to bare metal doesn't matter. Scrape it, sand it, sandblast it, put it through a cleaning cycle in the oven, acetylene torch, on the coals of a charcoal BBQ, chemical strippers... BARE METAL IS BARE METAL. That said, there are a few hints and tips. If you strip the old seasoning with super-high heat or chemicals, be sure to also scrub the heck out of it afterwards. Why? Because any impurities in the old seasoning will still be on the surface of the iron and they have to come off to make sure there won't be anything between the iron and the new seasoning layer. Also, high heat can promote oxides of some alloys used in cast iron, and you don't want them there either. Personally, I recommend a drill and a sandpaper disk, as mechanical methods also smooth out rough areas. After getting it down to bare metal, clean it by washing in soap and water, RINSE WELL to be sure no soap remains and then dry it with a paper towel, and dry it again by heating it a bit on the stovetop or in the oven for a few minutes. Why? Because most water in the US (and elsewhere) is hard water, and if the water is allowed to evaporate instead of being removed, it'll leave behind minerals on the surface of your iron, and you don't want that. Also, heating it a bit makes sure that any water in the nooks and crannies (not pores, cast iron is NOT POROUS) is gone, and the residual heat allows the fat/oil/grease you will apply to thin out a bit.

              2: put on a light coat of oil. Now when I say light coat, most people just don't get it. Touch your nose to a nearby window. Look closely at the mark that's left. That's skin oil, and that's how thick (thin) the initial seasoning coating should be. Almost any kind of oil or grease will do (technically oils are fats, we just call any fats that are liquid at room temp oil... I'll be referring to whatever you use as fat in the rest of my explanation). Crisco, vegetable oil, lard... all good. NOTE: Whatever you use should be pure fat (oil). Lard is OK if it's processed, but for the initial seasoning don't use impure oils like baconfat or butter, and I prefer not to use olive oil either. Dampen a paper towel with oil (or swipe it through your can of Crisco) and wipe the fat onto your cast-iron piece. Inside and out is fine, but make sure you don't miss any areas. Next, grab a clean paper towel and wipe OFF as much of what you just wiped on as you can. Thin, thin, thin layer. You know those sites that tell you to put your pan in the oven upside-down so excess oil can drip out? Bogus. There shouldn't be enough oil on the piece to drip. If there is, you're doing it wrong. We're talking a layer of oil whose thickness is measured in angstroms... nanometers... a hundred molecules. Ten thicknesses of the initial seasoning should still be thinner than a sheet of paper.

              3: Bake. 400 degrees F (or 200C) for an hour is a good rule of thumb. Why not 300? 500? Why an hour? Ok, first, what you're doing is actually trying to make the fat (oil) decompose. Fats are basically some hydrocarbon chains hanging onto a few water molecules. At room temperature, nothing special happens, as there's not enough energy around to allow the molecules to react in any way. But add enough heat and the fat molecules will begin to decompose. A water molecule (technically an oxygen atom from the air combined with a hydroxyl radical from the carboxylic acid group for any organic chemistry majors, but we'll keep it simple for this discussion) separates from the hydrocarbon chains and evaporates. This leaves behind the hydrocarbon chains, which tend to link up together (polymerize). Now, as more and more of these hydrocarbon chains link up, the fat (oil) becomes more solid... think of it as turning the Crisco into nylon. But it doesn't (or shouldn't) stop there. The heat allows the carbon atoms to join together, which means a hydrogen atom is 'squeezed out' of the chain of hydrocarbons. This process is called pyrolysys or carbonization.
              Now, all that said.. why 400 degrees? Because lower and the reactions might not happen at all, or just the polymerization will happen (sticky, gooey seasoning), or it'll take too long. Higher temps and the reaction might proceed too quickly. Remember that water evaporating? If the polymerization happens before the water (steam) can escape from the thickening fat, it'll stay trapped and form bubbles. Same way steam makes baked goods rise, except you want your seasoning layer to be more like a tortilla than a hamburger bun. That's also why you want the layer of fat (oil) to be thin. Thick layers trap the escaping gases and become full of bubbles... spongey, soft and not very robust. Also, higher temps mean oxygen from the air is more likely to react with the hydrocarbons and degrade the polymerization. Plus, all ovens vary in their temp accuracy, plus factors like infrared heat from coils, etc. mean any recommendation has to be somewhat tempered by variableness. Now.. all this polymerization and pyrolysis doesn't happen instantly. The molecules must be lined up just right and energy has to be absorbed at the right time for all this to happen. Think of flipping a quarter until you get heads 10 times in a row. You know it'll eventually happen, but it might take a lot of flipping. Now imagine doing this with a million quarters, except that you can flip all million at once. After 10 flips, a few of them will all have been heads... after 100 flips, more.. and after 1000 flips, maybe half will have come up heads 10x in a row. Basically, it just takes time for all this flipping and randomness to give you the results you want... which is all million quarters having come up heads 10x in a row. Same with seasoning. You have to keep the fat at an elevated temperature for long enough for all the polymerization and carbonization to happen. Yes, you can increase the heat (flip the quarters faster!) but remember the gases need to escape without leaving a bubble.
              So... 400 degrees for an hour is just a good general guideline that'll work for almost everyone.

              Oh, and after it's been in the oven for an hour? Turn the oven off and let the pan cool in the oven, slowly, with the door closed. This gives all those reactions more time and saves energy.

              Is there more to it? Well, kinda. Cast iron isn't porous, but if you look at it under a microscope you'll see flakes of carbon embedded in an iron matrix. The seasoning primarily attaches itself to these carbon flakes, which is why it sticks to the pan. Remember my cleaning advice? Anything that prevents the carbon in the seasoning from bonding to the carbon flakes in the iron will make the seasoning more likely to flake off.

              How does the seasoning get thicker? Well, cooking is heat, oil and time, so a wee bit of oil will go through the whole polymerization and carbonization process, adding to and thickening the seasoning. How thick is a good layer of seasoning? No thicker than a sheet of paper or two.

              Can you do additional oiling and baking to add more layers to the seasoning? Sure, but don't go overboard. Two or three initial layers is fine, more is overkill.

              How do you clean it? Is soap ok? Should I use kosher salt, etc? A green 3M scrubbie and hot water is, in my opinion, the best. Kosher salt is recommended because the salt acts as an abrasive, and kosher salt has larger grains that don't dissolve as easily. Why spend money on kosher salt when you probably already have a plastic scrubbie? Basically, anything that's safe to use on Teflon is safe to use on seasoning. As for soap, a properly seasoned pan is IMPERVIOUS to soap. There are no pores to trap soap, and soap doesn't dissolve seasoning. If you doubt it, try washing a piece of anthracite coal. That said, I avoid soap because soap plus the mechanical scrubbing action DOES tend to remove the semi-polymerized coating of oil that will eventually become part of the seasoning. I do however occasionally use soap on my cast iron, but I'm more likely to just wipe it off well with a paper towel and put it away, or scrub with a scrubbie when needed.

              Phew, science!

              4 Replies
              1. re: ThreeGigs

                bravo!

                1. re: ThreeGigs

                  Wow. Is there a way to save that as "Cast Iron 101"?

                  1. re: ThreeGigs

                    ThreeG, I am going to save this as my go-to primer. I'm still struggling with CI seasoning, so will try the above.

                    But some follow-up questions:

                    -- I thought optimal temperature for CI seasoning was dependent on type of grease used/its smoke point? I.e., some types of grease have smoke pts below 300, others above 400..and thought somehow the grease had to get just to (?) smoke pt or above it (??). Can you pls address this?

                    -- Re rinsing well with water -- doesn't the whole (now bare/unseasoned) pan rust instantaneously upon contact with water even if just slightly then (per Chem's earlier post) and then you're back to square one -- having to scrub off the rust that JUST appeared from the rinsing, then rinse off the steel wool bits or whatever you scrubbed the new rust with, then rust comes back with that new exposure to water, etc..? I posted about this once before and don't think I fully resolved it except to think that I might try scrubbing off the rust with just oil and salt so hopefully wouldn't have to rinse with water (assuming rust as opposed to steel wool is somewhat safe to ingest if there are a few remaining bits left in the pan).

                    I do know that I got caught in this vicious cycle, and this was just trying to get rid of a small rust patch on a new pre-seasoned Lodge!

                    Thanks in advance.

                    1. re: iyc_nyc

                      "I thought optimal temperature for CI seasoning was dependent on type of grease used/its smoke point?"
                      It's not smoke, really. It's haze, or smog. Water vapor plus oxides of nitrogen, and the occasional ammonia or methane molecule. If you can see the smoke, you are producing too much of the gases too quickly. Yes, some oils have higher or lower *visible* smoke points, mostly because they are a combination of lipids that decompose at various temps. All fats will smoke at around 350 degrees F, it's just that with some, there isn't a large enough constituent of easily decomposed lipids to be able to *see* the resulting gases. Like a pan of water, just because you don't see steam, doesn't mean the water isn't evaporating.

                      "doesn't the whole (now bare/unseasoned) pan rust instantaneously upon contact with water even if just slightly"
                      Not really. Iron oxide formation takes time, and while you might get a molecule thick layer of rust, it'll get wiped off by the paper towel when you dry it. Any further iron oxide formation will be minimal at most since without water or an electrolytic solution (like SALTY WATER, ahem), rusting happens quite slowly. Also, over time, the seasoning process will tend to pull the oxygen atom off of the iron atom, leaving the iron atom free to re-bond to the cast substrate, or mix with the polymerizing oil where it'll help catalyze the polymerization process. Now, you know salt water causes rust to form faster. And you know that after using oil and salt you'll have to wash with soap and water (I mean, you wouldn't leave *any* salt on the pan while seasoning, right?), meaning that at some point you'll be exposing your bare iron to salt water when the salt dissolves in the water. So put your salt away and scrub with some steel wool or sandpaper to get rid of rust, then wash it, dry it with a towel and then DRY it with heat. Lightly oil and season.

                  2. I'm a member of the Wagner and Griswold society ( http://www.wag-society.org/ ) and folks on there (not !: I'm too poor ;-) have literally thousands upon thousands of dollars invested in rare, antique cast iron cookware. They also--as do I--have plenty of vintage cast iron that is just for home use. Virtually every one of them recommends cleaning crusty old cast iron either in lye (as in "oven cleaner" or "drain cleaner"--I use the drain cleaner, dissolved in a Rubbermaid tub of water, as its odorless. For just a few pieces, the EasyOff method, where you place the items in plastic bags out in the sun between sprayings, works just as well but the fumes are nasty!), or a process known as electrolysis. Some, also, put less valuable (as in, stuff for we Ordinary Folks ;-) in a self-cleaning oven cycle.

                    Then, there's a general consensus that whichever temperature you use for seasoning, it MUST be hot enough to exceed the seasoning oil's smoke point, thereby producing carbonization (and, of course, smoke; open your windows!) to burn off the oil that would later turn rancid and gunky, and create that beautiful, slick, glossy ebony surface to which we all aspire.

                    It's really quite simple and very, very reliable once you get over the initial hesitation caused by working with such "scary" ingredients. I have been a WAGS member for about 18 months, and have cleaned and seasoned probably 75 pieces of vintage cast iron in that time, and none of them were damaged and all turned out beautifully seasoned and ready to cook. I use Crisco (after experimenting with both olive oil and PAM) for seasoning. I always wipe and wipe and WIPE to get the excess off the pieces, before seasoning, so the oil doesn't pool up and make dribbles and blotches. If the piece I'm working with is too "raw" (the surface is grey and new-looking, rather than black) I first cook the iron UN-oiled at about 475 degrees for a hour. Then I let cool, oil, wipewipewipe, and put in an oven that I've set for 475--500 degrees (it's okay to put the iron in a cold oven) and heat for about an hour once it reaches the temp. IF the pieces are valuable, I take them out every 15 minutes (wearing industrial strength heat protection gloves,such as "Ove Gloves") and wipe the interior/concave parts of the piece (like the bowl of the skillet) with paper towels held by long-handled locking tongs, to further reduce the blotching effect of excess oil.

                    Let cool in the oven. After each cooking session, wash with hot water and a Tuffie pad (or, for burned on foods, use oil and kosher salt, first, and scrub with a paper towel) and lightly mist with Pam and wipe dry to store.

                    Here's a WAGS member who has a great blog describing cast iron care:
                    http://blackirondude.blogspot.com/200...

                    IF you do not season your pan at a hot enough temperature to carbonize that oil, you'll end up with a gunky, sticky pan that attracts dirt. A properly seasoned piece of cast iron glows with a satiny sheen and yet is NOT oily to the touch.

                    Here's a pic of some Griswolds that I cleaned. They were covered in gunk and rust before the treatment I described. That egg just SLID right out of the pan, by the way...

                    P.S. I have to disagree completely with the poster who recommends sand or bead-blasting a piece of cast iron. There is absolutely NO BETTER WAY to completely destroy the patina and ruin the value of a good piece of vintage cast iron, than by doing this....

                     
                    15 Replies
                    1. re: Beckyleach

                      I'll agree, one shouldn't sandblast antiques, nor should you use any mechanical method on something whose value lies in its pristine-ness. Then again, not all cast iron is 80-year old Griswold, some of it is simply 5-year old Lodge.

                      What purpose does baking bare cast iron at 475 for an hour serve, aside from promoting oxide formation on the surface?

                      1. re: ThreeGigs

                        Doesn't seem to promote any oxide, aka rust. Is your oven damp?

                        I have no scientific explanation for it, but it appears to result in darker coloration once the entire seasoning process is finished. You don't have to take my word for it, however. I'm just following in the footsteps of people who've devoted their lives to cast iron restoration, and that's the advice they gave to me.

                        And, generally, any piece of cast iron over 40 years old was better made and of higher quality due to the finishing process, than newer iron, so should be treated with due respect. They don't have to be Griswold (which was made until the 1950's, by the way). Sand and bead blasting give a "dappled" effect to the surface that never seasons away, completely. I've seen photos and comparisons, side by side, of just ordinary Joe cast iron, and the blasted stuff just doesn't ever seem to recover from the process.

                        1. re: Beckyleach

                          When I'm talking about an oxide layer, I'm talking about something microscopically thin... so thin you can see through it but it changes the color of the surface. Kinda like how copper looks after a while. Chemically, I see no benefit from pre-baking raw iron pieces, and I would tend to argue that it's detrimental to the bond between the seasoning and the cast iron.

                          One good thing about sandblasting is that it can get the rust out of heavily pitted areas. As for bead blasting, depending on the material you use to blast with it won't harm the metal one bit. Glass or walnut shells are frequently used for stripping surface coatings on thin sheet metal, especially automotive applications like body paint. However, most homeowners with a sandblaster will wind up using sand, which might remove some metal and damage the 'crispness' of some cast-in details.

                          1. re: ThreeGigs

                            I am sitting here at my desk goofing off online while my laundry is churning in the washer and I ended up here. I was stunned to read someone recommending sand or bead blasting cast iron cookware. No, no, no don't do that. It screws up the molecular structure in some weird way that makes the pan get all blotchy and ugly when one tries to season it.
                            I've blasted CI a couple times. Once I wanted to removed the nasty peeling nickel on a lid but I only had the top top done as the inside was perfect and I didn't want to mess it up. The other time I had a very old round bottom pot with a tiny hole I wanted to use as a hanging planter. The blaster cleaned it up for me and I spray painted it wrought iron black and it's been hanging from the cover over our deck ever since.
                            Becky in her posting above knows what she's talking about. No point in me say it all over again. Also, I saw Kimbell do his thing on TV with kosher salt but all I do is put a bit of water in the pot or pan, heat it a bit, no need to boil. Then I dump out the water and wipe clean with a paper towel, spray with Pam, wipe it again and put it away. I cook almost totally with cast iron and all my stuff is clean and beautifully seasoned. It continues to be re-seasoned with use so scratches or whatever are repaired continually. Always make your final step a shot of Pam wiped around and your pan will sty wonderful forever.

                            1. re: ThreeGigs

                              Preheating the piece at a high temp does cause a reaction on the surface of the pan which I would have to assume is an oxide layer. The process that Becky has described cause the pans to be a very beautiful black color after the piece is seasoned. The piece will be dark without this process but will lack the deep black luster that many collectors cherish. If you just want your pan to be seasoned and don't care about how black it is then preheat your oven and go. If you don't preheat your oven you will most likely get very nice lines on the bottom of your piece from the condensation that forms on your oven racks.

                              Sandblasting or beadblasting a piece is never recommended and if your pan had collector value before it was blasted it won't when you are done. It is a very effective way of turning a $50 piece of cast iron into a $5. If that is your goal then be my guest but don't promote your destructive methods to the rest of the public that is simply looking for a good way to clean a skillet. Send them to a collectors website where they can get advice from people with decades of experience who have cleaned and seasoned hundreds or thousands of pieces.

                              I am not entirely sure why sandblasting causes pieces to have a very blotchy look when seasoned but it is very distinct. I would have to think that this occurs as a result of the high speed impact of the media (which is generally harder than the cast iron) with the iron itself.

                              As for walnut shells or other materials that are softer than cast iron, they generally will not remove all of the rust. So you either clean the piece with tried and true cleaning methods or you destroy the collector value of the piece. Even if the skillet is a 5 day old Lodge and has no collector value as of right now who is to say that it won't in the future.

                              Just some words from a guy that has cleaned and seasoned hundreds of pieces and has never sandblasted any of them :)

                              1. re: jeffbob312

                                "As for walnut shells or other materials that are softer than cast iron, they generally will not remove all of the rust."
                                Thousands of auto body repairmen will dispute your claim.

                                And this is a cookware board, not a COLLECTORWARE board. Like you said, if someone doesn't care about the exact shade of black on their cast iron, season and go. Hell, you could send the thing out for chemical vapor deposition of an amorphous carbon layer if you were truly nutso about the perfection of the seasoning.

                                "don't promote your destructive methods to the rest of the public that is simply looking for a good way to clean a skillet. Send them to a collectors website"
                                Are you serious? Should I send people to a collector's website when they want to know how to get a stain out of their sink? Anyone who has a valuable piece should, I think, know not to use extreme mechanical methods to clean their cast iron. Give the readers on here a little credit.

                                FYI Cast iron looks 'blotchy' after you sandblast it because you simply cannot get an even texture on the CI. Angle of impact, spray cone diameter, overlap, etc. all mean slightly uneven surface roughness. Which when seasoned lightly, gives you an uneven look to your seasoning. Use it a bit and the uneven look goes away as the seasoning builds up (on the inside).

                                1. re: ThreeGigs

                                  So they make car bodies out of cast iron now?? You can get the loose rust off of the piece and I will not dispute that. The piece will still have "hard" rust on it when you are done. Electrolysis is the most effective way of removing rust. If it is good enough for the Smithsonian then it is good enough for everyone else to use.

                                  The trouble with people promoting sandblasting any cast iron piece is that hundreds of people that do not know how to clean cast iron will read this and think it will work for all pieces. I could point to dozens of EBay listings for collectors pieces that have been destroyed using blasting. Most of the people that buy the items are new collectors and have no idea they have just bought junk. Check out the thousands of dollars worth of items this guy blasted:

                                  http://completed.shop.ebay.com/dscott...

                                  You can keep blasting away as that is your right. I will continue to promote the non-destructive cleaning of these wonderful pieces of history.

                                  1. re: jeffbob312

                                    "Electrolysis is the most effective way of removing rust"

                                    Agree.

                                    Although I think you two have both made your points and future readers can make better decisions based on you two's argument points.

                                    1. re: jeffbob312

                                      "So they make car bodies out of cast iron now??"
                                      No, they make them from steel, which rusts. You know, the same rust that forms on cast iron.

                                      Look at the first post please. You're simply setting up a straw man and knocking it down. This is not a thread about collectibles, nor 'historical cast iron treasures'. It's about some cruddy old cast iron cookware that someone got off of Craigslist. It's definitely NOT a "How do I clean a rusty old Griswold #27 corn/wheat pan?" (if it were, my answer would be "Don't clean it, let the collector you sell it to do that").

                                      On a side note, read my post again. I didn't 'recommend' sandblasting, only listed it as one of several methods someone could use to get their pan clean. And oddly, it was mostly tongue in cheek, as I suspect very few people have a sandblaster at home, and if they did I suspect most of them would still use a drill and sanding disk. Why are you going on about sandblasting, yet making no mention of sanding which should also affect the cast iron?

                                      If cast-iron care posts on a cookware board are so important, why is it you only have posted in this one thread? You're arguing in the wrong place, really. I'm guessing Becky pulled you in from the Wagner society boards. What you need to do is make a thread on here along the lines of "How can I tell if my cast iron is valuable?"Telling people that the bast way to remove rust from their $1 yardsale Chinese imported cast iron pan is electrolysis is disingenuous, at best.

                                  2. re: jeffbob312

                                    If you are unsure as to the value of your cookware, sandblasting it will make this easy to determine. No collector of cast iron cookware will buy a piece that has been abused in this manner. The collector value is now zero, and any experienced collector can spot them at 20 paces. Sandblasting would also be very effective to remove bird droppings from one's vehicle, but most people choose to use a chemical detergent that does does not also damage the original finish.
                                    If you want to sandblast your trailer hitch before painting, that would be fine, but I don't think it's a good idea for cast iron cookware, antique or new. It changes the surface texture in a way that can NEVER be corrected. Is this how you would clean grandma's fine china or crystal? Iron is actually softer than glass.

                                    The same lye that is used by collectors to clean cookware has been used in this way for over a hundred years. Also it is used to process some foods, and is listed as an ingredient. While it is a "harsh chemical", it is easily washed off with soap and water. Lye will remove the black crud from cast iron because it is alkaline.
                                    IF there is rust, a 50/50 mix of vinegar and water will remove rust. OH NO! Not another "harsh chemical"!?! Vinegar is an acid, and will soften the rust so that you can remove it with a soft steel wire wheel on a drill. Never use an angle grinder to wire wheel a cast iron item though, the high speed will damage it. The vinegar solution is good for soaking items for an hour to a few hours, but should not be left for more than that, as the acid will eventually start to eat away at the iron too, not just the rust.

                                    With simple , effective methods such as lye, for crud, and vinegar for rust, it seems silly to forever damage what might be a valuable item by sandblasting it.

                                    1. re: jeffbob312

                                      I didn't know about the pre-heating lines, Jeffbob. Thanks for the info. Will be more careful in the future...I also noticed that, after I switched from an electric oven to a gas one, I have to be more careful, as gas ovens are moist when they first fire up.

                                  3. re: Beckyleach

                                    Becky,

                                    My guess is that you are trying to form a layer of Fe3O4 by heating the pan dry. It is also known as black iron oxide. By creating this bluing layer of black iron oxide, the cookware is more resistant to red iron oxide -- rusting.

                                    1. re: Chemicalkinetics

                                      I won't pretend to understand the science and chemistry involved, but I can attest that preheating the iron before seasoning will result in a darker finish. I first did this to ensure that the item was completely free of moisture, but continued the practice based on the results. I only know that it works.

                                      1. re: Chemicalkinetics

                                        Thanks, Chemical! I spent my high school chemistry class watching the spitballs fly. The teacher was completely inept and the class was rowdy. Glad to learn something new!

                                        1. re: Beckyleach

                                          Becky,

                                          I think it is a likely explanation -- producing Fe3O4 (magnetite) also known as black iron oxide. Like you, I also dry heat my cast iron and carbon steel cookware a bit before addining the oil. Here are two quotes:

                                          "Many people put bare cast iron in the oven at high temperature for an hour before adding oil for seasoning because it blackens the pan. I thought this was just aesthetic, but now I realize it may create a layer of magnetite."

                                          "Unlike red rust, black rust is protective and prevents corrosion. Also, things bond better to magnetite than bare iron (for example, polymerized fat)."

                                          http://sherylcanter.com/wordpress/201...

                                2. Cleaning and seasoning are two different deals.

                                  First cleaning:
                                  -dish soap: it's a good thing. If things are way greasy, dish soap and hot water have no substitute. I think the whole thing about it making the food taste like soap is hooey. Maybe this was an issue when grandma made soap from lye, tallow, and sweepings from the fireplace.
                                  -abrasives: salt, steel wool, scotch brite, copper scrubbers, sand: they all work. Start with least abrasive (salt) and get as medieval as you need to.
                                  -once cleaned, rinse in very hot water, dry, and immediately proceed to seasoning.

                                  Now to seasoning:
                                  With a paper towel, rub a thin layer of oil all over. I can't overstate that the oil should be spread as thinly as possible. Now place the piece upside down in a hot (450F) oven or, even better, a gas grill outside, and let it bake for a good hour. After an hour, turn off the gas and just let it cool on its own.

                                  The pan will now be seasoned and look...horrible. It probably won't be all blackened and lovely, but brown and splotchy. Where the oil was a little thick, the surface might be sticky or gummy. At this point, you could just use it -- it will work just fine, and eventually look all black and satiny.

                                  Or you could repeat the seasoning a time or two. It will get darker each time.

                                  Oil: Use what you have. Olive oil and butter are probably poor choices. Soybean oil (sold as vegetable oil) has worked fine for me. Some folks swear by Crisco. Canola and peanut oil have very high smoke points -- I suppose they could work, but expect them to take longer. (You are trying to "dry out" the oil, so to speak.)

                                  Care and feeding: Use your cast iron as much as you can (not just for frying bacon). I like giving the pans a spritz of PAM once the pan is heated up. Ignore the old crocks who refer to cast iron as "non-stick" -- food WILL stick unless the pan is greased, and food WILL stick if food goes into a pan that hasn't been heated thoroughly. The OC's mean well, but you will be happier if you have reasonable expectations

                                  Most cleaning can be accomplished by scouring with salt and rinsing with hot water. (Dish soap only if the grease is unmanageable). A nylon brush can also help with scrubbing. A good soak is called for if things are really burnt on.

                                  Once clean and dry, set on a burner and wipe the inside of the pan with a little oil. Once you get a wisp or two of smoke, turn off the heat and let it cool on the stove top -- your pan is ready for whatever is next.

                                  1. The two methods I WOULD NOT use are putting iron in a hot wood fire to burn off the carbon or sandblasting cast iron. With both you take a chance of damaging to iron in different ways

                                    1. After more than 20 years of research, practice, and cooking I have perfected the below method and it is gospel!

                                      Materials needed for “seasoning” your pan: Crisco or palm oil, clean cotton rag, paper towels (don’t use vegetable oils as they tend to be sticky.) Crisco should not be used for cooking because it is hydrogenated oil but it is the best for seasoning. This is because it is converted into a polymerized oil & carbon layer that seals the pan but does not enter into your food.

                                      1. Preheat the oven to 250F. for 15 minutes (it is imperative to preheat gas ovens to remove all moisture.) Place clean, uncoated item in the oven, set at 250F, and bring the item up to temp for 20 min. The pre-heat before applying Crisco or oil is essential to this process. Using an oven mitt, remove pre-heated item and set on a large baking sheet or newspapers (place hot pads under sheet to protect counter.)

                                      2. Wipe on Crisco or palm oil with a clean rag, inside and out, and then wipe off all the excess with paper towels. Be careful not to leave particles from paper towel. Wipe it down until it looks like you've wiped it all off. Even if it looks dry, it's not. Very little coating is needed. If you TRY to leave a little bit on, then that’s too much. This prevents forming “splotches.” Now it won’t drip off so just put it right on your oven rack.

                                      3. Return it to the oven, still at 250F, right side up on the oven rack, for 10 min. Then, using an oven mitt, take pan out, wipe once more with folded up paper towel to remove excess oil. Return pan to the oven, and raise the temp to 300F. After another 10 min. , take pan out, wipe inside once more with paper towel to remove excess oil. Return to oven, raise temp to 450F, and bake for one hour. Open a window as this produces some fumes.

                                      4. After one hour at 450F just turn off the oven and leave it in, without opening the oven, to let it cool slowly for at least an hour.

                                      5. Repeat steps 2 through 4 above four more times, but only apply Crisco or palm oil on the cooking surface. For the last time bake at 450F for 1 ½ hours (90 minutes) to set the finish. Let cool as in #4 above. Your cookware should be nearly black and not sticky. Your pan won't be sticky if the carbonization is complete.

                                      The pan will gradually turn jet black and glossy after using it to cook foods. Be gentle with utensils until it develops a hard, slick black coating. Use a stainless steel spatula (not chrome-plated steel) with a perfectly flat, smooth edge and rounded corners so as not to scratch the nice black layer you have made. A well-used one is ideal as it has its edges smoothed and rounded from use. Clean with hot water only - no soap or detergent. Avoid cooking bacon, ham, or anything with sugar until it develops a hard, slick black coating. The sugar in bacon and ham tends to stick to the pan until it has been used for awhile cooking other foods.

                                      Right before using it wipe a little Crisco or spray a light coat of Pam on the cooking surface. Wipe off with a paper towel. This cleans and prepares the surface. Now add whatever fat or oil you are going to use for cooking. NEVER start heating a cast iron pan on high! This can cause a hot spot and permanently warp the pan. Pre-heat with medium-low heat for a couple minutes. Or place the pan in your oven and set it at 350 degrees and let it preheat for 7 minutes. This is the best method for larger skillets (#10 and larger) and Dutch ovens. Then you can put it on the range burner and turn it up to medium-high (if you are searing meat.)