Can you use soap on cast iron?
Yes, you can use soap on cast iron. The idea that soap will ruin cast iron dates back to a time when soap contained harsh, abrasive substances such as lye. In those days, soap would corrode and damage the seasoning and underlying iron of cast iron cookware.
Modern dish soaps are mild and don’t contain chemicals that will harm your cast iron with gentle use. In fact, a small amount of dish soap is the best way to clean stubborn stains and prevent them from allowing flavors to migrate into your next meal.
If the idea of simply rinsing and wiping your cast iron clean with a towel is unsettling to you, go ahead and use a mild dish soap and a sponge or brush to clean your cast iron cookware. Both your seasoning and your skillet will remain intact and unharmed.
There are many ways to clean cast iron
Soap, salt, sponges, scrapers, scrubbers, spatulas, and more can be used in different ways to clean a cast iron skillet. The most important thing is to get it clean enough for your personal preferences without damaging the seasoning. Outside of that, anything goes, as any residual bacteria will be killed the next time you heat up your pan.