How to remove rust from cast iron and re-season the pan

Step by step: how to remove rust from cast iron and re-season the pan

Safety first. Wear gloves when scrubbing, since steel wool splinters and rust dust stain skin. Seasoning at 450 to 500°F can smoke: open a window, run the range hood, keep pet birds out of the kitchen, and use oven mitts, because the pan stays dangerously hot for an hour after the oven is turned off.

1. 1

   Judge how deep the rust goes

   Light orange haze or a few spots will come off with a scrub. Thick, flaky rust or pitting over most of the pan may need a vinegar soak first. Either way, the pan is almost always salvageable unless it is cracked.

2. 2

   Scrub the rust down to bare metal

   With gloves on, scour the rusty areas with steel wool or a rust eraser and a little water until the orange is gone and you see dull gray iron. Work the whole pan, including the bottom and handle. Expect some of the old black seasoning around the rust to come off too.

3. 3

   Soak heavy rust in diluted vinegar (only if needed)

   For rust that will not scrub off, soak the pan in equal parts white vinegar and water. There is no set time: check it often and take it out as soon as the rust lifts, because once the rust is gone the acid starts on the iron itself. Never leave it soaking unattended for hours. Scrub again right after.

4. 4

   Wash with warm soapy water

   Wash the pan with dish soap and a stiff brush to remove rust dust, steel wool fibers and any vinegar. Rinse well. The water will run reddish brown at first and then clear.

5. 5

   Dry it completely on the stove

   Towel dry the pan right away, then set it on a burner over low heat for a few minutes. Bare iron can flash rust in minutes, so do not skip this. The pan should look evenly dry and gray.

6. 6

   Wipe on a very thin coat of oil

   While the pan is warm, rub about 1 teaspoon of oil over every surface, inside and out, then wipe it off with a clean towel as if you made a mistake. It should look matte, not shiny or wet. Too much oil bakes into a sticky layer.

7. 7

   Bake it upside down for one hour

   Put foil on the lower rack to catch drips, set the pan upside down on the center rack, and bake at 450 to 500°F for one hour. Turn the oven off and let the pan cool inside.

8. 8

   Repeat the oil and bake two or three times

   One coat protects the iron, but a pan scrubbed to bare metal does better with two or three thin coats baked on. When it is even, dark and slightly glossy, it is ready to cook in.

Why does cast iron rust?

Cast iron rusts when water reaches bare iron through thin or missing seasoning. Lodge’s troubleshooting guide lists the usual causes: leaving the pan in the sink, running it through the dishwasher, letting it air dry, or storing it somewhere damp.

• Soaking it in the sink, even briefly, or leaving water in it after cooking.
• Drying it in a dish rack instead of with a towel and low heat.
• Storing it with the lid on, which traps steam and humidity.
• Cooking acidic sauces for a long time in a newly seasoned pan, which wears seasoning thin.
• Long storage in a damp basement, camper or garage.

Which rust removal method should you use?

Use the gentlest method that works: most home skillets only need steel wool and a re-season.

Lodge’s rust restoration steps are the first row: scour with steel wool or a rust eraser, wash with warm soapy water, dry on low heat, oil thinly, and bake at 450 to 500°F for one hour with the pan upside down. Made In adds that extensive rust may mean fully stripping the pan before re-seasoning.

Should you use the oven self-clean cycle or oven cleaner on rusty cast iron?

No. A self-clean cycle can reach temperatures high enough to warp or crack cast iron, and lye oven cleaner strips seasoning but does nothing for rust. Steel wool, a short vinegar soak and patience are safer for a pan you want to keep.

For the oil, Lodge’s seasoning guide suggests vegetable oil, melted shortening or canola. Pricier oils are not required. The thin layer and the full hour at temperature are what turn oil into hard seasoning.

How to keep cast iron from rusting again

Dry it with heat and leave a whisper of oil after every wash. That one habit prevents nearly all rust.

• Never soak the pan or put it in the dishwasher.
• After washing, warm it on a burner for 1 to 3 minutes, then rub in a few drops of oil.
• Store it uncovered, or with a paper towel inside to absorb humidity.
• Cook with it often. Regular cooking with fat builds and maintains seasoning.

For day-to-day washing, follow our guide on how to clean a cast iron skillet. For rust on tools, patio furniture or other steel, see how to remove rust from metal.

Mistakes to avoid

• Leaving the pan in a vinegar soak unattended, which can etch the iron once the rust is gone.
• Scrubbing off the rust and then letting the bare pan air dry, so it rusts again before you oil it.
• Applying a thick coat of oil before baking, which leaves a sticky, blotchy finish.
• Baking the pan right side up, so oil pools in the bottom and turns gummy.
• Running the oven self-clean cycle to strip a pan, which can crack or warp it.