How to Remove Rust From Cast Iron
We've all been there, cruising a yard sale and suddenly you spot a pile of rusty cast iron pots and pans. You spot the perfect cast iron skillet, but it's heavy with rust. Most of the time, you can follow some simple steps to remove rust from cast iron without damaging the cookware. We are going to walk you through the process we find works the best for removing rust from cast iron, and we'll also let you know how to identify rusted cast iron that's beyond salvation.
Is Rust on Cast Iron Dangerous?
That rusty cast iron skillet looks unappealing to cook in and it'll probably stick and burn your food, but it's not likely that cooking in rusty cast iron will harm you. However, cooking with rusty equipment will make your food taste like rust. And that's not what most of us are going for. Rather than cook on a rusty cast iron pan, simply clean it up. We'll show you how in this article so you'll never worry about rust in your food again.
How Much Rust is Too Much Rust?
It never fails that you find the ideal pan at a great price, and it's rusty inside and out. It's easy to know if the pan is too far gone. The first step is to feel the cooking surface with your fingers. Rust is rough, but also flaky. If you can feel flaky pits on the surface, the pan is probably not worth saving. But rough, flaky rust on the outside of the pan is not a concern unless the metal is seriously pitted.
Rust on used cast iron pots and pans can help you identify cracks that mean the pan is dangerous to use and useless for cooking. You'll sometimes see rust forming in and around cracks, making them a little more obvious than when a pan is evenly oiled. Don't waste money, time, or energy on cracked cast iron cookware.
How to Restore and Season a Rusty Cast Iron Skillet
We are going to set out four steps for cleaning any rusty cookware. If you follow them, you'll gently (and successfully) remove rust from the cast iron without causing any damage. Removing rust from cast iron may require a significant investment in physical effort, but it's a cheap process using tools and ingredients you probably already have in your kitchen anyway.
After stripping a cast iron skillet using any of these methods, you'll need to season it again to prevent rust and encourage a non-stick surface. Don't worry we'll show you how to season a pan once you know how to clean it.
Step 1 – Wash It
You'd be surprised how many times a really rusty looking pan just has a film of rust on it that washes off with warm water. You can use a few drops of mild dish soap to help remove particles and debris. Use a nylon brush to help loosen surface rust from the pan. If the rust is gone, then you are ready to season the pan. If not, it's time to get more aggressive.
Step 2 – Vinegar
This is the easiest way to remove rust from a cast-iron skillet or griddle. Vinegar can be used to remove rust from cast iron. Just make a 50/50 mixture of white vinegar and water. Fill a bucket or a sink that's large enough to fit the cookware and submerge for 30-minute intervals. Vinegar will clean the rust, but too long of a soak may damage the metal. Once the rust is gone, vinegar begins pitting the surface of the cookware.
You can use a brush or a ball of aluminum foil to scrub off most of the surface rust. When you can wipe the rust from most of the pan easily, it's done soaking. Now you can wash it in hot water and check to see if the rust came off. If not, you can take more steps to get the pan clean.
Step 3 – Steel Wool and Sandpaper
The next step to take is to use fine grade steel wool to remove the remaining rust. Try an O-grade or OO-grade steel wool to remove rust without damage. Working the steel wool back and forth, up and down rather than in circles will prevent swirl marks should you get too aggressive.
You can also use a fine grade of wet-or-dry sandpaper to clean rusty cast iron pots and pans. A 1600 grit sandpaper and warm water is a great way to remove burnt-on grease and rust.
Step 4 – Grinding
This step seems scary but it's totally safe as long as you use your head. Set up a grinder with a steel wire wheel and gently strip the rust. You don't want to put pressure on the grinder because it can damage the metal. If you can, avoid using a grinder on the cooking surface of a cast-iron skillet. A grinder is a great way to clean up the outside of your cast-iron cookware though, and it saves a ton of elbow grease.
Seasoning Your Rust-Free Skillet
Now that your prized yard sale-find pan is free of rust, you'll want to keep it that way. You can use much the same process for the inside and the outside of the pan to get a good layer of seasoning on the metal and keep rust from returning.
Seasoning the Outside
The pan must dry thoroughly before seasoning – you can dry it while preheating the oven for this step. Once the oven reaches 450 degrees, use a clean paper towel or rag and gently wipe a quality cooking oil on the surface. You want to cover the cookware completely, but also keep the layer thin. Place a cookie sheet with a layer of foil on the bottom rack and put the pan in the oven upside-down. You want to bake the pan until the oil stops smoking and loses its glossiness, about 15-20 minutes.
Carefully remove the pan and set it on a heat-resistant surface to prepare the pan for final seasoning.
Seasoning the Cooking Surface
Now that the outside of the pan is seasoned, simply wipe the inside surface gently with vegetable oil or a cast iron seasoning product. You want a thin layer that's evenly distributed. Everyone has their favorite oil for seasoning, but flaxseed oil, avocado oil, and vegetable oil are all good choices.
Place the cast iron in the oven and bake until the oil stops smoking. It'll take 10 to 15 minutes to smoke. Carefully remove it from the oven and set it on a heat-resistant surface, like the burner on the stovetop.
The Last Step
Now that your cast iron pan is restored to glory, it's easy to keep it that way. When you use your cast iron, do not wash it with soap. Soap strips the seasoning layer from the cookware, so you'll have to re-season the pan again. When you make a meal that's really sticky, cleaning the pan right after use is our favorite way to keep from having to regularly restore cast iron. You can make sure your cast iron doesn't stick by putting a small amount of oil on the surface when not in use.
If you follow these steps, you'll be able to restore any cast iron cookware easily using common items in your household kitchen. Cast iron makes a great way to cook delicious meals for your family, and good pieces are heirlooms gratefully accepted by generations of future kitchen masters. If you're looking for more care tips, or for our favorite cast iron skillets, check out our ultimate cast iron guide next.
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