Regardless of the extent of the rust, there are options beyond throwing out rusted cast iron. For severe rust that covers most of the cookware surface, take the piece to a machine shop to have it sandblasted and restored to raw cast iron, then season the skillet immediately.
Cast iron needs to be cherished, and rust is the enemy. The easiest and fastest way to remove rust from cast iron is Evapo-Rust®. It will spare your knuckles, as there is no scrubbing with brushes or steel wool involved. It is also safe to use on your cooking supplies.
You can use two methods to give cast iron a good scrub: salt or a stiff brush. Pour a quarter cup of salt into your pan and use a flat-edged kitchen utensil to push the salt around the pan. The salt will begin to discolor as you scrub. Remove all grains from the pain to avoid corrosion, then apply a light coat of oil.
To tackle items with significant corrosion, submerge your rusty tools or knives in a bowl of white vinegar and let them sit overnight or as long as 24 hours. Once they have had a good soak, remove them from the vinegar and scrub the rust off with steel wool, a scouring pad, or a wire brush.
Use of Vinegar
By using a sponge wipe away the rusted area. Vinegar can also be mixed with tartar cream to create a paste. Apply this paste to the area from where rust is to be removed and wait for a minimum of 5 minutes. Rinse the area clean and dry it off.
The vinegar solution will dissolve the rust, but once that's gone, it can penetrate further and start eating away at the original cast surface of the pan, the ultimate death sentence for your skillet. If that happens, retire it to a piece of farmhouse-chic kitchen decor.
Scrub and wash your pan
Scour the rusty sections with steel wool or the Lodge Rust Eraser. Then wash the pan with warm, soapy water. This step may remove portions of the seasoning, but that's okay because we're preparing to re-season the pan.
WD-40 can be used to remove rust from your cast-iron stovetop depending on how much you use and how long you leave it there. If you want to get rid of it quickly, you can try adding more WD-40 or applying the same layer over again.
We do not recommend using CLR on cast iron. CLR can compromise the metal.
Contrary to popular belief, you can use a small amount of soap to clean cast iron cookware! Large amounts of soap can strip the seasoning off your pan, but you can easily re-season your pan as needed. Can I use steel wool or a metal scrubber to clean my cast iron pan? No!
The Cause:
Occasionally, the seasoning on your pan may break down and leave black specks, especially if the cookware is not well-seasoned, but it is not harmful in any way.
Yes, Coke contains phosphoric acid which helps remove rust from cast iron. Pour Coke on the rusted area and wait 15 to 20 minutes for the acid to break down the rust. Then wipe the pan with a scrubby sponge or dish towel. Repeat this process until the rust is completely gone.
Steel wool works very well on cast iron rust. Afterwards, rinse with water, dry completely, then coat with Crisco or other cooking oil followed by seasoning in a 350 degree oven for 30 minutes. Repeat seasoning if needed.
Doing so can cause the all-important seasoning on the surface of the pan to flake off. This not only results in unappetizing black flakes in your meal but also degrades and chips away at the seasoning, which is paramount when cooking with cast iron.
To clean, just use mild dish soap (that's right, it's okay to use a little soap!) and a scouring pad or a cast iron pan cleaning brush. Wash it, scrub it, rinse it, then wipe it out well and season it with a few drops of oil and store with a paper towel covering the cooking surface.
The simplest way to remove a lot of rust from cast iron is to make a slurry of Bar Keepers Friend and a couple of tablespoons of water in the pan and scrub the rust off using a stainless steel scrubber. We recommend wearing rubber gloves. Again, wash, dry, and re-season your pan afterward.
The vinegar-and-salt mixture needs time to break down the rust. This can take anywhere from one to three days. Check the tool periodically to see if the rust has softened. Once the rust has softened, use a metal brush or steel wool to scrub off the surface.
Common cooking oils like olive oil will gradually produce seasoning, but won't be as effective as grapeseed oil. Canola, other vegetable oils, and shortening are a little better.
Method: Use 2-3 tablespoons of citric acid in a bowl of hot water. Place your metal item fully into the bowl and let it sit overnight. Remove and scrub off lingering rust with a brush, before rinsing and patting dry.
Strong acids will dissolve rust, but they will also dissolve paint, finishes, and sometimes even the metal itself. Hydrochloric acid (which is also called muriatic acid in its diluted form), as well as phosphoric acid and sulfuric acid may be used in rust removal formulas using strong acids.