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Nov 21, 2008 12:58 PM

rust on cast iron pan

My beloved cast iron pan has developed some rust.
Do I toss it and buy another, or can it be saved?

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  1. No do not toss it. Cooks Illustrated just did a segment on this a few weeks ago where Chris Kimbal took a really hopeless looking CI pan and brought it back to life. Of course, I don't recall exactly what he did (I'm sure someone else will know). Seem to recall he may have put a fair amount of oil in it and heated it until very hot. Then scoured (no soap). I would imagine it might take some time to bring your seasoning back, but it will happen. Your CI will outlive you.

    1. Id remove the rust with a piece of steel wool and then re-season it if the sport is on the the inside cooking surface.

      1. There must be three thousand threads on Chowhound on how to restore cast iron.

        Basically sand it down to reach the rust layer, and reseason.

        For further information, use "search" or see this

        1. My quick response would be to use some pumice (used in gas grills) with oil and scrub the rust away. I prefer to stay away from salt scrubs as salt just promotes another rust cycle. Steel wool = snag city, no joy...

          1. Is this rust on the inside (cooking) surface, or outside? Is it deep, or just a surface layer of orange?

            Don't worry about outside rust; just make sure the pan is dry when stored.

            For light inside rust, try removing it with a regular kitchen scrub pad. If you have a cleaner like Bar keepers Friend, try some of that. Then oil and season the pan.

            Deeper rust, especially if flaking, needs more aggressive cleaning.

            22 Replies
            1. re: paulj

              Thanks all.
              The rust is not heavy, and it is on the inside.
              Just made me nervous to see it.
              I am not going to go the lye route, but will certainly try the other methods, and then reseason.
              If they don't work I will buy a new one.

              1. re: erly

                It may be as simple as cleaning with an oily rag. Your seasoning layer is likely still intake if its a light layer of rust. Coat pans with oil to store to prevent this.

                1. re: erly

                  It will work.

                  What you need to ask yourself is why did it rust to begin with. Cast iron doesn't just develop rust because it's a bad pan or because it's old, it's because of the way it was handled or stored. If you're storing your pan under the sink or in another moist environment (laundry room?) there's the source of your problem. If you let it sit in your sink with water in it overnight, there's another potential source. Point is, a new pan won't solve your problem if you're habits are the source of the problem.

                  1. re: HaagenDazs

                    The pan is 10 years old, .. used regularly,... but I noticed a slight buildup of grime,so I filled it with water boiled it and let it sit overnight.
                    Now I know better.

                    1. re: erly

                      Well... there ya go.

                      You can boil the water in it to help loosen some grime just don't let it sit in there.

                      Many people recommend using a kosher salt scrub to regularly clean a cast iron but I think that's a huge waste of salt and money. Salt isn't expensive, but compare it to a scrub brush and some hot tap water. Anyway, this would be a good time to use a salt scrub on your pan. Just dump a cup or so in your pan (depending on how big it is) and then use a wad of paper towels to scrub the heck out of it. That will help remove some of the rust but it will also scrub out much of the grime at the same time.

                      1. re: HaagenDazs

                        How bad is your skillet? If you have buildup and some rust you can completely clean and reseason it and it will be just like new! Do not throw it out. If you have a self-cleaning oven, just put it in and put a layer of foil on the bottom of oven to catch the rust and grime that will fall off, close and turn on the self cleaning option. Lots of smoke so open your windows. I do all of mine at the same time. A few hours later you will have a brand new skillet. I wash mine good, dry it, put some heat to it to really dry it. Then coat it with a light coating of vegetable oil and bake for a couple of hours, while adding a new coat every 30 to 45 min. It will come out like new.

                        I just did 4 and a lid today! They are great!

                        1. re: Daggerdoll

                          Save yourself the smoke and fire hazard -- season your cast iron on your grill outside.

                          1. re: MikeB3542

                            Well I followed instructions, and the pan was almost as good as new.
                            Then I noticed a slight rusting on the bottom, and decided to try Rhonda's suggestion and put it in the self clean oven.
                            Didn't get a lot of smoke, and when it came out, I was surprised that some more rust color appeared.
                            This method works.
                            Washed it off, and the pan looks like new.
                            I can wipe it with a damp cloth, and there is absolutely no residue, or discoloring on the pan.
                            So thanks all, and Rhonda, great additional tip.
                            It is now in the oven seasoning.

                        2. re: HaagenDazs

                          ""Many people recommend using a kosher salt scrub to regularly clean a cast iron but I think that's a huge waste of salt and money."" ... ""Anyway, this would be a good time to use a salt scrub on your pan.""

                          What is up with your change of mind?

                          Salt is the best known cause of rust, so why use salt to add another layer of rust?

                          1. re: HaagenDazs

                            First, you don't need kosher salt. Second, you don't need a whole CUP. Just a sprinkle. Third, you don't use this to remove rust, you use it to maintain a pan by polishing off any bits of food from a well-seasoned, just cooked-in pan.

                            1. re: mlgb

                              First, most people suggest using Kosher salt because it is more abrasive (larger grained) than regular table salt.

                              Second, a sprinkle will usually not be enough to clean up what you are cooking because 1) you have to at least add enough salt to absorb the fat/grease in the pan and 2) then you need enough to actually scrub up the bits of food all around the pan. When cleaning carbon steel woks (similar to cast iron in terms of treatment and cleaning) the Chinese have developed bamboo scrub brushes... they don't use salt.

                              Third, I was suggesting that this be done not necessarily as a primary rust removing tool, but be used to remove "some of the rust" as I said above, especially considering that the rust was "not heavy" (as mentioned by the poster) meaning not severe or significant.

                              1. re: HaagenDazs

                                Actually, the paper towel serves the oil-absorbing function.

                                A well-seasoned pan will have very little food stuck to it. A fine-grained grit polishes nicely.

                                1. re: mlgb

                                  There are 2 kinds of food that are often cooked in something like a cast iron pan. Something that is inherently dry (cornbread, pancakes) and other things that can leave some residue (bacon, eggs). If I do say, cornbread I don't even bother running it under water. There's nothing left in the pan but a fine coating of fat. If I cook bacon and eggs, I usually use hot water and a scrub brush. The brush does the exact same thing that the salt does (in a well seasoned pan, like you mentioned), only you don't have to use the salt. Tell me the advantage of using salt over a brush.

                                  1. re: HaagenDazs

                                    You get a shinier, slicker surface with the salt polish. I rarely need to use a scrub brush or even water. Just the salt and paper towel.

                                    I do however, have an older pan with a smooth finish. When I have had occasion to use one of the newer, especially prefinished, sand-cast pans I notice inferior stick-resistance, necessitating on occasion more drastic measures such as a few drips of dish soap soap!!!! hot water!!! and scrubbies!!!!

                                    1. re: mlgb

                                      That's kind of my point - you said you rarely need to use a scrub brush. So you're saying that they are just about the same thing, the brush might even be better. The only reason that it would be shinier or slicker is because you don't get rid of as much oil/grease.

                                      1. re: HaagenDazs

                                        If you'd like to actually learn something rather than just trying to prove you're right, I'm saying that the salt polishes the seasoning and removes minor gunkus, so that the pan is slick enough to be nonstick (apparently a condition that you have difficulty achieving). I cook anything and everything in my cast iron skillet, which I've had for maybe 20? 30? years. I almost never have a sticking problem, unless I totally burn something with sugar, etc.. In that case I'm using soap and am removing some of the seasoning . I don't use a scrub brush for regular maintenance cleaning.

                                        1. re: mlgb

                                          I'm not trying to prove I'm right, I'm saying that the salt and the scrub brush are the same thing. My only complaint and/or reason for not using salt in my clean up duties is because I find that it is a waste.

                                          1. re: HaagenDazs

                                            Yikes! Cast iron really brings out the crazies. Look, the stuff is well nigh indestructable. Scrub it clean however you wish: salt, Barkeeps Friend, drano, brillo. Just make sure it is rinsed well in hot water, dried immediately, and re-seasoned immediately. Unless you have completely nuked your seasoning, re-seasoning need be no more complicated than a quick wipe with some sort of oil (Crisco, olive, lard, canola, whatever!) and heat it on the stove until smoking. If the seasoning HAS been nuked, grease it up and set it on the grill upside down for an hour or so, and you are back in business. Real simple -- there are no black arts involved. Peace and love, y'all!

                                            1. re: MikeB3542

                                              This "crazy" doesn't need to "reseason" after each use. It isn't necessary to wipe a pan down with oil "or whatever" unless it's going into long term storage. Dust magnet. Yuk.

                                              1. re: MikeB3542

                                                Yeah - and this crazy doesn't waste salt. ;-)

                                                1. re: HaagenDazs

                                                  I don't waste a CUP of salt, water, fat, or energy. Just a sprinkle of salt (less than tsp) and a paper towel.

                                                  1. re: mlgb

                                                    I hear ya - I use a scrub brush and you use salt. I think my way is better but to each their own.