@cast_iron_chris: The seasoning on cast iron is a protective barrier made up of polymerized oil. Not all of the oil polymerizes- some of it carbonizes, turning into actual carbon and giving the pan that deep, dark patina we all love. The polymerized oil forms a chemical bond with itself and the pan. The carbonized oil doesn’t bond chemically but gets trapped under layers of polymer, which is why it doesn’t wash away. Together, they create a nonstick, rust-resistant surface that just gets better with time.