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remove burned on carbon from cast iron?

I have a few pieces of heirloom cast iron which have been in my family for years. They are covered in layers of black hard carbon, or whatever it turns into. How can I get the pans back into shape? I want to use them, so don't want to make them unfit for food.

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  1. You can use something called CARBON-OFF pick it up at SMART & FINAL,but if it's only on the outside of pan don't bother I think it add character to the pan.I have a set of handme downs which have been cooked on for 50+ years .Everybody loves the build up on the exterior of the pans.I clean the interior w/green scrub pad & a bit of D.W. liquid,then rub them with oiled paper towel.When using CARBON-OFF make sure area is well ventilated.Outside on newspaper & rubber gloves.It's magic for all your good non coated cookware.

    1. Carbon-off works. So does Mex (try the hardware store). Use rubber gloves and a spackle knife to get off thick, old carbon deposits. Then put an inch of salt in the pan and in the oven @ 350F for an hour. Rub the salt into the pan to get up all the dreck you can. Then wipe out with some oil on a rag until it comes clean. I do this to all my iron pans once every six months, then re-season them.

      1. If the "carbon" on the inside is smooth and of nominal thickness, that is patina, and is a natural non stick coating which is desirable and the goal of seasoning iron cookware, so I wouldn't touch it, same on the outside. If there is a thickness of emulsion or burnt on foods try scouring with steel wool or one of the previous suggestions and reseason the cookware. I second the use of a scotchbrite pad (I use the sponge with scotchbrite on one side for just about all dish washing, selecting the right side for the task) and dish soap to clean up cast iron, even though it inhibits the seasoning process a little, it is the easiest way to clean after cooking, reseason with a little oil and reheat to drive off the water if you expose the cast iron which would rust and react with food, as needed.

        1. Before you expend a lot of arm energy, try putting the pan in an oven with a self-cleaning feature (typically runs two hours), and see what comes off that way.

          1. -----

            Fortunately, I have access to a good torch (torch having 2-tanks, of which one has the oxygen tank, other tank having the flammable gas) that will knock off the carbon deposits almost upon contact with the right flame setting. It works like a charm on both cast iron and on aluminum.


            1 Reply
            1. re: RShea78

              My Dad used to clean Mom's cast iron with his welding outfit! You bring back a memory.

            2. You can use oven cleaner (outdoors) on your cast iron pans. It may take a couple of applications. My cast iron skillet has some burned-on stuff on the outside (not on the bottom), I just ignore it.

              1 Reply
              1. re: Seattle Rose


                Kind of pulling an opposite face here. My dad at one time,insisted on the oven cleaner method. Then with fresh water rinsing, the cast iron needed a good sanding or scrubbed off with steel wool, as it would take on a fine rust as it dried. Then back to the process to season it again.

                BTW- We came across with the torch method (a bit later on) when granny somehow broke the handle off her favorite 2 burner griddle. Dad wanted to clean it first but granny said it would take forever to season it. Dad welded the old one back on, but a ring formed of the heated area, and the carbon crud fell off in the process. When the area looked so pretty, dad figured a torch could do the rest and it did. Granny claimed it seemed to have a better surface even though the bottom was torched. She didn't need to season it again.

              2. Try pouring in some kosher salt and buffing the interior surface smooth with an old rag. The salt breaks down into a fine powder before it can scratch your pan, but it has enough abrasive power to get the caked on deposits off the cooking surface. Just reseason after you do this.

                1. Thank you all for the advice. These pans were on my grandmothers stove all the years I knew her. The thickness of the gook is so bad that when I placed the pans on a fire, the smoke filled the house. I think I'll try the 'Carbon Off" for starters, and then (heh heh) the blow torch. Everyone should have one around for creme brulee, right?

                  1. My family always threw them into a bonfire and let it all burn off. Then of course, you have to reseason them with cooking oil.

                    1. heat water in it to a boil, boil water in it for 5 minutes, scraping with a wooden spoon til you turn the heat off. That should get off a lot. Perhaps not all, but you will notice a significant improvement.