It’s easy to think that we should throw away things when they get rusty. That doesn’t need to be the case with your favourite cast iron skillet though. I’m going to walk you through some easy ways to restore your cast iron skillet, griddle, pan, pot or other cookware.
Why Bother Restoring Rusty Cast Iron?
Cast Iron pans can last generations if treated right. A little bit of rust won’t truly damage them.
Whether your pan is an antique, has sentimental value, or you just don’t want to buy another one – don’t give up too soon on it.
On the other hand, some cast iron might be too far gone, there are some things you can’t fix:
- Warping of the bottom of the pan making it unusable on induction or electric stoves. You can see this by putting it on a flat surface and seeing if it wobbles. It should still be useable on a gas stove though.
- Cracks in the pan. Small cracks won’t stop you cooking with it, though be careful as they could worsen. If it’s split, forget about it.
- Fire Damage. If it has turned red (redder than rust) then it is fire damaged. This is serious damage and is hard to fix. You could try sanding off the red part but the pan may be a goner.
- Pitting of the surface. A small amount of pitting isn’t a big deal. A large amount isn’t great – food will get trapped in it. Again you can try sanding it, but at some point, there won’t be much pan left.
Removing the Rust
The easy way
If the pan is newly and lightly rusted it may be very easy to remove the rust. Get an old rag, or even a paper towel and drip some oil on it. Sunflower oil will do. Wipe the rusty part and see if it comes off. If it does, great, no need to bother with the rest!
The hard way
The hard way is to scrub your iron cookware. Scrub with soap, and detergent. Scrub hard. Use abrasives like steel wool. Basically almost the opposite to how you would usually clean your cast iron pan.
Normally you want to protect the seasoning on the pan. Now you will need to get rid of the seasoning to get at the rust.
This means a lot of elbow grease, strong detergents, and hard abrasives. It’s likely you will take some of the metal as well. That doesn’t matter too much.
If you have the equipment, you could even sand the pan down.
If this isn’t working, or is too much work, read on as there is something else you can do to help.
The Vinegar Acid Bath
Don’t let the title put you off, I’m not suggesting anything dangerous here.
Before I go on, let me explain that acids and metals react. This is why you don’t cook (acidic) tomatoes with cast iron.
An acid bath will react with the rust and remove, or at least loosen it. It will also react with the rest of the metal. If you leave it too long it could cause pitting.
Vinegar is an acid. Acids can react better diluted so I would suggest a 50% cheap vinegar and 50% water solution. It depends on your vinegar (which is already mainly water). You may need experiment to get the right amount.
Leave your cast iron in the vinegar acid bath for no more than an hour. Don’t leave it overnight. Suspend it, or turn it around half way through so all of the pan is exposed to the vinegar.
Once it’s out try scrubbing it again and see if the rust comes off. You will need to repeat the vinegar acid bath / scrubbing cycle until all the rust has come off.
Alternatives To The Vinegar Acid Bath
Other Sources of Safe Acids
Any safe acid will work – many soft drinks included. Coca cola is acidic for example. The acid in soft drinks is already diluted so you don’t need to mix it with water.
Lemon juice is acidic, but that sounds expensive for the amount you would need! Maybe lemonade?
All these are experiments- I recommend sticking to cheap vinegar, but by all means try them.
Oven Self Cleaning Cycle
If your oven has a self cleaning cycle you may be able to use this. Pop the cast iron in the oven and set to self clean.
You may need to be careful with this treatment as there is a risk of heat damage to the pan (which is irreversible).
There are some recommendations out there to use electrolysis to help strip the rust. Actually it even reverses the rust and turns it back into iron. I would suggest avoiding this. Electrolysis, using water generates hydrogen (explosive and flammable) and oxygen (helps things explode and burn). Not a great combination! Not to mention, who has a spare car battery lying around to do this?
Even so, if this does interest you; this video talks through the process. It also shows some other methods for cleaning cast iron. It’s a good video to watch for background:
After Stripping The Rust
Once you have restored the pan, it will immediately start rusting again. This is especially the case if you stripped the (protective) seasoning as well.
To avoid this the best thing you can do is to season the pan straight away.
If you don’t have time for that, then cover it in oil. Any room temperature food grade oil should do. I would suggest sunflower oil. You should still season it as soon as possible, but the oil will give some temporary protection. (Think how the oil on a bike chain protects it).
Also, remember to be careful what you cook in it! Cast iron cookware is more susceptible to damage by acidic foods.
Stripping the rust varies from super easy (wiping it with an oily paper towel) to super hard (repeated scrubbing and vinegar baths).
Cast Iron cookware isn’t the easiest cookware to own. In many ways I prefer my Teflon pan which has none of this fuss. But when a nonstick pan gets damaged I throw it away. Cast Iron is made to last, it just sometimes needs a little TLC.