Will soap ruin cast iron? Using soap will not ruin your pan. It is totally fine on enameled cast iron, and on plain cast iron, too.
While soap will not hurt your cast-iron pan, water will, because it will cause the metal to rust, and so that is the thing you should not use on a cast-iron pan.
In short, yes, it is safe to wash cast iron cookware with mild dish soap or castile soap. However, avoid strong degreasing soaps and detergents to prevent damaging your pan's seasoning layer.
After you've used your skillet, use a sponge to scrub it with water. But don't let it soak in water, as this can cause rusting. If it still needs a bit more attention, add some kosher salt to the pan and scrub with a damp sponge. The salt acts an abrasive cleaner without disturbing the seasoning.
The reason given for this rule is that if you were to use soap, it would strip the cast iron of its “seasoning.” Seasoning is a layer of polymerized oil that's baked into all cast-iron cookware. It's what gives a cast-iron skillet a non-stick (really more like an “easy-release”) surface.
Cooks for generations didn't use soap on cast iron pans because the soaps were made with lye and vinegar, two ingredients that will absolutely strip seasoning and can even damange the pan's iron. Today's aerosol oven cleaners are often made with lye, or sodium hydroxide.
Even though a rusted cast-iron pan doesn't necessarily present a health concern, it's still not recommended that you cook on it. The rust might add an unpleasant metallic flavor to your food. Plus, it makes using the skillet much more difficult.
The Cause: Rust forms when the cookware is exposed to moisture for extended periods of time and is not harmful in any way. If cast iron is left in the sink to soak, put in the dishwasher, or allowed to air dry, it will rust.
Cast Iron Skillet Cleaning Method: Salt and Paper Towel
The method: Pour 1 cup coarse kosher salt into the still-warm skillet. Use a folded kitchen towel to scour. Discard the salt and rinse the skillet with hot water.
Clean cast-iron skillet after every use
Wipe interior surface of still-warm skillet with paper towels to remove any excess food and oil. Rinse under hot running water, scrubbing with nonmetal brush or nonabrasive scrub pad to remove any traces of food. (Use small amount of soap if you like; rinse well.)
Step 1: Wash the Cast Iron Pan Well
Once you're done cooking in your pan, go ahead and wash it with some warm soapy water, wiping it with a kitchen sponge. If there are a few stubborn burnt-on bits, you'll be fine using the synthetic scrubber on the back of many kitchen sponges, as it's not as harsh as steel wool.
Use a fine grade steel wool pad and scrub the pan surface, inside and out, to remove rust and debris. Wash the residue with hot water and mild soap if needed. Once you have cleaned all the residue off the cast iron skillet, wash and dry your skillet as noted.
Oxidation is a common consequence of using dish soap to wash cars. Oxidation is rust, and it forms due to a combination of sunlight, moisture, and oxygen exposure. When automotive wax and paint are jeopardized or in poor condition, dish soap applications can quickly lead to rust formation.
Without the protective layer of carbonized oil called seasoning, cast iron is susceptible to rust. Even a well-seasoned pan can rust if it's left in the sink to soak, put in the dishwasher, allowed to air dry, or stored in a moisture-prone environment.
Soak your cast iron in vinegar (or don't).
Mix equal parts water and distilled white vinegar and add it to a container that will fit your rusty cast-iron skillet, such as a bucket or a deep foil pan. Make sure the entire pan is submerged in the mixture, handle included.
Mix together equal parts basic white vinegar and water, and either add the solution to the pan if it's rusty only on the inside or completely submerge the pan in a bucket of the stuff to dissolve the rust all over. Letting it soak for about an hour should do the trick, depending on the damage.
Don't fill your cast-iron cookware with wine or vinegar. A splash for sauce or deglazing is OK, but tossing a significant amount straight into the pan undiluted will ruin your cookware, and your health.
Submerge your rusty cast iron cookware ensuring it is fully covered in Coke. Allow to soak for 12 - 24hrs depedning on the rust coverage. Rinse the Coke off with clean water. If needed, use a sponge to wipe off excess rust then dry with a clean cloth.
Don't let it soak in the sink.
Truthfully, leaving your cast iron to soak in the sink is worse for it than any tomato sauce or soap will every be. Cast iron is porous, meaning that long exposure to water can cause it to soak up the moisture and eventually rust.
Place the pan in the oven: Place the cast iron upside down on the top rack of your oven. Place a sheet of aluminum foil or a foil-lined baking sheet on the bottom rack to catch any oil drips. Heat the cast iron for one hour at 350°F.
All cooking oils and fats can be used for seasoning cast iron, but based on availability, affordability, effectiveness, and having a high smoke point, Lodge recommends vegetable oil, melted shortening, or canola oil, like our Seasoning Spray.
Olive oil is a great option for seasoning your cast iron skillet because it is affordable and easy to find. It also has a high smoke point, which means it can withstand high temperatures without burning.
From a food-safety standpoint, the surface of a cast iron pan during cooking easily reaches upwards of 300 degrees, which is high enough to kill any bacteria that don't get washed away.