Cast iron cookware has become increasingly popular over recent years, but it requires a little bit of care and attention to keep in great working order.
First there’s the seasoning process, which requires baking a layer of oil in to create a non-stick surface.
And then there’s the exterior surface of the pan. This requires its own maintenance, as it takes the brunt of the punishment on the stovetop.
What’s the best way to clean the outside of a cast iron skillet? It’s not a complicated job, and simply requires you to following these steps:
- Heat a kettle of boiling water.
- Invert the skillet in your sink so the bottom of the pan is facing upwards.
- Gently pour the boiling water over the surface.
- Use a suitable scrubbing utensil to get the worst of the grime off.
- If that doesn’t finish the job, repeat using a cleaning agent (see later in this guide for more detail).
- Wash as usual with warm water once you’re done.
- Dry the skillet completely to prevent rust forming.
- Store as usual.
It’s not a complicated job by any means, but the devil is once again in the detail!
In the rest of this cleaning guide I’m going to talk about some of these processes in greater depth.
I’ll cover the kind of cleaning agents you should – and shouldn’t – use on your cast iron skillet.
I’ll also go into more detail about the best tools you should use when cleaning all kinds of cast iron cookware.
Finally, I’ve answered some of the most common related questions that readers often have about cast iron care.
(My home cookware guide contains plenty more tutorials and buying tips!)
Before We Start
The most important thing to keep in mind when cleaning a cast iron skillet is this:
Minimize water contact to prevent rust building up.
That means getting the clean-up job done as quickly as possible, and making sure the skillet is bone dry before returning it to its storage space.
Cast iron is notorious for attracting rust over time. Even a little bit of moisture can wreak havoc if it’s left in contact for long enough.
If the standard clean doesn’t get rid of all the grime, you can repeat the process using a few chemical-based helpers.
I’ll start with the least abrasive. If that doesn’t work, move down the list. The idea here is always to avoid doing more damage than you’re trying to fix.
#1 Standard Dish Soap
It’s always a good idea to begin this job using your standard – mild – kitchen detergent. 9 times out of 10 this will be enough to finish the job.
#2 Bar Keeper’s Friend
This is the classic kitchen helper, and I think everyone should have a can of it somewhere in their cupboards!
It’s useful for cleaning the bottoms of all kinds of cookware, and you’ll rarely regret adding it to your supplies.
#3 Baking Soda / Vinegar
Both of these common kitchen ingredients are useful for cleaning up pots and pans. See the article I’ve just linked for more information on how to use these ingredients.
When it comes to a cast iron skillet, however, you should only really use vinegar when you need to remove a lot of rust. You’ll find more information about this in the Q&A section towards the end of this article.
#4 Oven Cleaner
I hesitate to list this one here because it really is a case of bringing out the big guns when nothing else has worked.
Try everything else in this list first, and be particularly careful about letting any of the oven cleaner come into contact with the interior surface.
Don’t leave it on the exterior for long at all, clean quickly with your scrubber, and make sure the pan is thoroughly rinse and dried after you’ve finished.
This method should be considered the last chance saloon for your cast iron skillet!
Tools For The Job
There are some very useful tools that make this task much easier.
Some of these are useful for many other cleaning jobs too, and so are worthy investments to make in your kitchen.
You’ll need one of these if your cast iron skillet has been neglected for a long time.
They’re really useful for levering off the worst of the damage, but without the risk of scraping the pan.
Even if you only have very light surface damage on your skillet, you’ll find these useful for all manner of clean-up jobs.
- Heat resistant up to 500 degrees F.
- Non-stick, Stain resistant and Odor resistant.
- Hygienic silicone scraper BPA-free.
When you’re cleaning up cast iron surfaces, you want something tough enough to get the job done, but not so tough that you risk damaging the surface.
You’ll need to re-season your pan after giving it a good scrub, but you obviously don’t want to cause any damage.
Scotch-Brite pads are a very popular option, as they can be cleaned in the dishwasher for re-use. They’re also made from recyclable materials, which is always a bonus!
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I always recommend starting with Bar Keeper’s Friend when it comes to kitchen clean-up jobs. It’s the mildest, most effective option on the market.
Even if you find yourself having to use something more abrasive on the bottom of your cast iron skillet, I promise you’ll get value from this stuff across all kinds of home and kitchen cleaning tasks.
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I’ll answer some of the most common questions about cleaning cast iron skillets in the next section.
Before that though, I wanted to include a few useful tips you should keep in mind while following the cleaning instructions I’ve outlined at the start of this guide.
Tip #1 – Cleaning Stubborn Grime
If you’ve performed the first thorough clean but there’s still stubborn grime baked on, grab a wooden or silicone spatula.
While running the outside edge of the skillet under warm water, use the spatula to gently lever the muck off. Be patient here, as it’s much better to work firmly but gently.
Don’t use metal utensils when you’re working with cast iron! It’s far too easy to add scrapes and scratches to the cooking surface. This is especially true when you’re applying more force than usual to the most problematic areas.
As always, make sure the cast iron skillet is thoroughly rinsed off and dried completely before putting it away.
Tip #2 – Oil After Cleaning
A popular method for keeping cast iron skillets looking – and performing – well, is to lightly oil them before putting them into storage.
Just add a few drops of the same oil you use for seasoning to a paper towel. Work that oil into the interior and exterior surfaces of the skillet.
Less is more here. You don’t want to add a sticky skillet back to your cupboards. The idea is just to add a gentle, protective sheen.
Tip #3 – Prevention Is Better Than Cure
The outside of your cast iron skillet is always going to take more of a beating than the inside. It is, after all, sitting in constant contact with the heat source.
Try to get into the habit of giving the exterior a little extra TLC during the regular wash. That way you’ll stop the problem getting worse over time, leaving you with a more frustrating maintenance job.
Tip #4 – Appearances Can Be Deceiving
If the outside of your cast iron skillet is still looking a little worse for wear, there may not be anything you can do to restore it to its former pristine condition.
Different heat sources have different effects on cast iron material over time.
Sometimes it’s better to accept that the superficial damage is simply a sign of a skillet that’s been well-used!
Frequently Asked Questions
Finally, I wanted to answer some of the related questions people have about keeping their cast iron skillets in great working condition.
Should I Season The Outside Of Cast Iron?
Yes, the material inside and out is one and the same!
It takes very little extra effort to apply the oil to the outside of the pan as well as the inside.
Do so and you’ll provide a useful protective layer to every aspect of the pan.
Can I Use Steel Wool In Cast Iron Cookware?
It depends on whether you’re giving your cast iron skillet a standard clean, or going for full rust-removal.
For a standard surface clean? No. If you need to get rid of layers of rust? Yes! I’ll explain why.
Steel wool is an incredibly abrasive material for any kind of cookware. Although cast iron is tough, you’ll inevitably remove the seasoning layer by scrubbing it this way.
It’s much better to use a silicone scraper like the one I’ve highlighted further up the page.
If you’re trying to remove a lot of rust though, you’re going to have to re-season the whole pan anyway. For that reason, it’s fine to use steel wool to make a tough job that little bit easier.
What Is The Black Residue On A Cast Iron Skillet?
It’s completely normal to notice black residue accumulating on the surface of your cast iron skillet. These are carbon deposits.
This stuff is completely harmless, and is a carbon by-product of the oil you use during cooking.
Sometimes the oil breaks up during particularly intense cooking, and you may notice small amounts of it end up in the food.
It’s no better or worse for you than eating a little bit of dark crisp on a pizza crust. It might not look particularly appealing, but this is just part and parcel of cooking with cast iron.
If you want to minimize the production of this black stuff, stick to using oils with a higher smoking point.
They’re less likely to carbonize at high temperatures and create this residue.
Can You Use Dish Soap On Cast Iron?
It’s a common misconception that you can’t use dish soap on cast iron. The thinking goes something like this:
“Soap is designed to remove oil, therefore soap will damage your oil-based seasoning.”
This simply isn’t true.
Your cast iron skillet is not coated in a loose layer of oil. The oil is instead baked – or polymerized – into the surface during the seasoning process.
Using dish soap on cast iron is absolutely fine. Letting your cast iron soak, on the other hand, definitely isn’t.
This will cause rust to build up on the surface of the skillet, and add yet another kitchen chore to your growing list…
Can You Use Baking Soda And Vinegar On Cast Iron?
Baking soda is a popular option for removing very stubborn grime from cast iron cookware.
Just make sure you clean, rinse and dry the pan thoroughly before putting it back into storage.
Vinegar is also commonly used for removing rust from cast iron skillets and other cookware. For the long answer, I’ll refer you to the Uno Casa guide on this subject.
These are the important things to be aware of:
- Don’t soak your cast iron in vinegar for longer than 8 hours. Personally I consider this a stretch and wouldn’t leave it anything like that long!
- Don’t set and forget. Check in regularly to see how the rust removal is going. You want to keep the skillet in soak for as little time as possible, and so a small amount of rust will lift quicker than a lot of it.
- Try leaving it for just one hour and then scrub it with a nylon brush. If there’s still rust present, add it back to the vinegar soak and check in after another hour.
What’s The Best Oil To Season Cast Iron?
You’ll need to repeat the seasoning process regularly, and so it’s important to pick an oil that’s both affordable and readily available.
It also needs to have a high smoke point as well, as you’ll be heating your cast iron pots and pans up to a pretty high degree.
Cast iron manufacturer Lodge has a very useful guide to choosing the best seasoning oil.
In summary, the best oils for seasoning cast iron are considered to be:
- Vegetable Oil
- Melted Shortening
- Canola Oil
I’ll be very surprised if you don’t have a bottle of vegetable oil somewhere in your kitchen! That’ll be the best place to start.
A word of warning on olive oil, however. Although technically you can use this oil for seasoning, Uno Casa notes in its guide that the low smoke point of olive oil makes it less than ideal for the task.
When Should I Throw Away My Cast Iron Pan?
Not before you’ve tried everything!
Even some of the most sorry-looking cast iron skillets and pans can be bought back to life given enough care and attention:
- Start with the regular wash I’ve outlined in this guide, and try some of the more abrasive options if necessary. If you’re planning to replace the skillet anyway, there’s no harm in at least trying these more invasive cleaning chemicals.
- Many people who consider throwing away their cast iron pans do so because of the rust build-up. This can be fixed! Try the vinegar soak method I outlined earlier in this guide, but do check in on it regularly so you don’t over-soak the skillet.
That should be all the information you need to keep your cast iron skillet clean and cared-for (inside and out!)