I prefer to leave my washing up until after we’ve put the kids to bed. Then I pop as much as I can in the dishwasher, and hand wash anything left.
This is a complete no-no for cast iron! Any food or humidity is going to damage it. For the same reason you can never leave cast iron to soak. Iron rusts. If you are thinking “what about other metal, like utensils?”; well stainless steel is protected from rust . Cast iron doesn’t have these protections – which is why you have to be careful with it.
When to clean your cast iron cookware
You should clean your cast iron cookware as soon as possible after using it. As a guide, if the cast iron isn’t noticeably warmer than room temperature, you’ve left if too long.
I know, having kids, that it’s easy to leave it too long. You can’t always clean it as soon as you like. I would suggest that you at least get rid of any acidic food (like tomato), or water based liquid straight away. Oil and fat aren’t too bad if left for a little while.
One little reminder–enameled cast iron is easier to clean and you don’t normally need to be as strict in getting it done quickly. This article is focused on bare, “non-enameled” cast iron. If you can’t be bothered with all this, check out my enameled cast iron cookware guide.
Also remember carbon steel is the same as cast iron for maintenance purposes.
Before we go on let me address one of the opinions about using soap, or detergent, to clean your cast iron.
Soaps used to be made with Lye, this is a highly-reactive chemical, that would strip a layer of skin from anyone using it on their body. (This wasn’t regarded as a bad thing in the effort to get spotlessly clean. Of course now we understand this is a bad idea!)
Lye does react with metals, including cast iron, and the seasoning layer. So it will damage your seasoning. Worse, it will release hydrogen, a highly reactive chemical, which could start a fire.
So don’t used lye based soaps with your cast iron.
However I really doubt your soaps are lye-based. Home detergents do not normally contain lye.
So a normal dish soap is fine. If you aren’t sure, ask yourself, would you be comfortable sticking your hands in it? If it won’t harm your hands it shouldn’t harm your cast iron. (Just in case I do advise, using only a little, and washing the soap off quickly.)
What you need to clean cast iron pots and pans
Here is what I use:
A small amount mild soap, or detergent. There are mixed opinions about using this, so be careful. Lodge, a popular cast iron cookware manufacturer, says it’s OK to use a little soap or detergent. It can’t be too strong as it can strip the seasoning. If in doubt try without soap, but I prefer to use a tiny amount.
See my Lye explanation above, but a good test is–would you stick your hands in the soapy water? If the answer is “No” then don’t stick your cast iron pan in it!
Obviously don’t used scented hand soaps which aren’t meant for cookware. Use a mild, safe dish soap that you would be happy exposing your bare hands to for a long time.
Water at the same temperature as the cast iron. If you are doing this right, this means warm water. I put cold water on my hot Teflon pan all the time, but cast iron isn’t Teflon. With cast iron there is a risk that it will crack from temperature differences.
A non metallic, non abrasive, scouring pad, like the back of a sponge. Avoid steel wire, or a metal brush – they will strip the seasoning and scratch the metal.
Vegetable Oil. Non refrigerated and as long life as possible. Since you are using it for long term protection, it needs to last without going rancid. I use sunflower oil. High Oleic is the best for this. This is completely different to the seasoning oil I use because it is a different process.
Salt is an optional extra.
How to clean your cast iron
As you are using water, you should do this as quickly as possible. Leaving cast iron to soak is the worst possible thing you can do.
Before starting, scrape any food off with a wooden / plastic / silicone spatula. Then rinse the pan to get rid of any liquids. It’s easier to do this with a cast iron griddle, whereas pots and Dutch ovens are harder.
Scrub the pan with warm soapy water. Use as little soap or detergent as possible. If you find this works with no soap or detergent – even better. Don’t scrub too hard – you want to remove any food, not the seasoning layer you worked so hard to build. This is a rare case where putting less effort into scrubbing is a good thing.
Alternatively scrub with salt and water. Sprinkle the salt over any tough areas then keep on scrubbing (with soap if you like). The salt acts as a safe abrasive. It will help get food off the surface, without damaging the seasoning.
Rinse off the soap
Thoroughly dry. First dry with a towel, then heat in the oven or on the stove briefly. You need to get rid of any moisture.
Lightly oil. Put on as thin a layer of oil as possible, then wipe off any excess with a paper towel. It should be as thin as possible so it doesn’t drip all over your nice cupboard. It’s not pleasant to find a puddle of oil in the cupboard! Use long lasting food grade oil like sunflower oil. Oiling it will help protect it from moisture, like you oil the chain on a bike for example. (Obviously it’s not the same oil as you don’t cook food with your bike chain)
One you’ve finished, put a paper towel on the bottom of the pan to catch any moisture.
You should store it in as dry a place as possible. The reality of course is you will put your cast iron pan with the rest of your pots and pans which should be fine.
It’s a good idea to keep the lid off, or ajar, so that the cast iron can air.
What if it goes wrong?
If it goes wrong you are looking at three scenarios:
- You lost some or all of the seasoning through over enthusiastic cleaning
- It’s rusted
- You cracked the pan
The first easy to deal with. Just season it again.
The second is a bit harder, but you can see how this gentleman manages it:
(Or read my guide to restoring rusty cast iron.)
If you crack the pan, you will need to get a new one, unless you know a blacksmith. Sorry, there isn’t an easy fix to this, so be careful. Cast iron should only crack due to quick temperature changes – this can happen when heating or cooling.
Cooking with cast iron can be rewarding, but you do need to look after it.
The thing is, cleaning cast iron is simple:
- Scrap / rinse off as much food as you can
- Give it a light scrub, optionally with a small amount of soap or detergent
- Dry it using an oven or a stove
- Lightly oil it with a long-lasting vegetable oil
Whatever happens avoid extreme temperature changes as they will crack the pan. (Don’t pour cold water onto a hot pan!)