It is a good idea to clean your cast iron skillet after every use, but this does not mean you should scrub it clean with soap and water. In most cases, you should be able to rinse your skillet with water, then wipe it dry with a paper towel or clean tea towel. If there are any crispy bits stuck to the skillet, add a sprinkle of kosher salt to the skillet and scrub to loosen up those crispy bits. Once clean, wipe it dry as usual.