Washing Cast Iron Skillets: Yay or Nay?

Published Categorized as Kitchen
Cast iron cookware on a tablearinahabich /123RF

A good cast iron skillet can be your trusty kitchen partner for life—as long as you care for it well.

So you’ve bought a new cast iron skillet, and you’re eager to start cooking all sorts of delicious dishes in it… but the instructions for use and care say that it isn’t dishwasher safe.

How do you keep it clean? Can you at least wash it by hand?

Cast iron skillets should never be put in the dishwasher, or the seasoning will come off and they will corrode and rust. Instead, these skillets should be cleaned by hand, in the sink with a soft sponge and soapy water, then patted dry thoroughly for storage.

To wash your cast iron skillet, all you need to do is give it a good soap down with a squeeze of mild dish soap on a soft scrub sponge, and then a good rinse. I use the soft, non-scratchy side of the sponge to avoid agitating the seasoning.

What does “mild soap” mean? Essentially, any liquid detergent that doesn’t have a grease-removing formula and is relatively easy on your hands. My personal favorite, and the dish soap that I rinse my dishes with at home, is the German-made Frosch Natural Liquid Dish Soap.

Never soak your cast iron skillet and never let water—or other cooking liquids, for that matter—stand in it. The golden rule for caring for cast iron is to keep it dry at all times. Unless, of course, you want to practice removing rust from it.

Clearly, cast iron and moisture don’t get along. If you wash your cast iron skillet, you must therefore dry it, or you will have problems with rust. For this reason, some cooks heat their pan on the stove for 4-5 minutes over medium heat after patting it dry.

Doing so evaporates the residual moisture in the skillet so that, when you pull it out of your cabinets on the next day, it won’t have gotten rusty. (To first-time owners of cast iron cookware: this is a more common issue than you probably think.)

Can You Use Soap on a Cast Iron Skillet?

There are as many opinions as opinion givers when it comes to washing cast iron cookware with soap. And for a good reason: soap contains lye, and lye can easily burn through the seasoning on a cast iron skillet.

At least that was the case with the soaps our grandmothers used because the lye they contained came from soaked wood ash. It was chemically aggressive and could cut through organic materials like a knife through butter.

Today’s soaps contain chemically pure lye (sodium hydroxide) that doesn’t agitate the seasoning on cast iron cookware as much. Some soaps don’t even have lye or natural fat at all and are, in reality, synthetic detergents, Healthline reports.

Contrary to what most people think, cast iron cookware can be cleaned with mild soap. The trick is to do so briefly and sparingly; large amounts of soap and intense scrubbing can strip away the seasoning of your cookware, leaving you to reapply it.

Can You Skip the Soap?

Yes, if you haven’t cooked any stinky food in your skillet, you can always give it a quick rinse, pat it dry, heat it on medium for a few minutes, then let it cool and hang it on the wall or put it in the cupboard.

But if you made salmon for dinner and your pan smells like fish, washing it with soap is the only way to get rid of that fishy smell and flavor so that anything else you cook up in that pan doesn’t get imparted with them.

I’ve seen YouTubers recommend alternative cleaning methods, like scrubbing the skillet with salt or with baking soda. That being said, I don’t see them as significantly better (or milder) than a rinse with soapy water.

Never Put a Cast Iron Skillet in the Dishwasher

As you can see, the answer to “how to wash cast iron skillets” is as straightforward as answers can be.

It boils down to the fact that iron is highly reactive when it’s not coated with porcelain enamel and is unseasoned. So it tends to corrode through contact with the air—and to rust when it’s exposed to moisture for a long time.

You protect a cast iron skillet from rust by seasoning it. To season a pan, you use a lint-free cloth or a paper towel to rub a thin layer of cooking oil all over the interior, exterior, and handles. Then, you bake the pan face-down for one hour in a 450°F oven.

(You place the pan upside-down to prevent cooking oil from pooling on the bottom, which will hamper your seasoning efforts and require you to season it a second time around.)

When oils or fats are heated in cast iron at a high temperature, they change from a viscous liquid to a smooth, hardened surface by a process known as “polymerization.” This reaction produces a protective layer of seasoning molecularly bonded to the iron.

This layer acts as a barrier between the bare iron and the external elements such as air and water, safeguarding the cooking vessel against corrosion and rust. It also gives a slick, non-stick coating that prevents food from sticking to the pan’s bottom and sides.

Unlike non-stick frying pans, whose PTFE coating is sensitive to scratches but doesn’t react to anything, the seasoning on cast iron skillets can peel off easily if you boil liquids and prepare acidic foods in them or if you clean them with chemically aggressive agents such as dishwashing detergent.

The Bottom Line

Washing cast iron skillets with soap: a yay or a nay? The verdict is a resounding “yay,” as long as you use a mild soap, do it relatively quickly, and don’t put in too much elbow grease scrubbing.

Although the soap can sometimes be omitted, it’s practically the only way to get rid of the residual smell of pan-fried egg or seared salmon. (And who wants tonight’s steak to smell like yesterday’s fish filet, really?)

By Jim Stonos

When Jim isn't in the kitchen, he is usually spending time with family and friends, and working with the HCW editorial team to answer the questions he used to ask himself back when he was learning the ropes of cooking.