If a piece of cast iron cookware is only slightly rusted, and not pitted, or has a small amount of food stuck to it, brush it with a light wire brush or course scrubby and then pour Coca-Cola over it, then let it sit until it dries.
After it dries, spray inside and outside with Pam or rub on vegetable oil, then bake in a 350 degree Fahrenheit oven for an hour and a half. Put aluminum foil under the pan to catch the drip.
Let it completely cool before removing from the oven. The final product will …
— Mark Kelly, Lodge Cast Iron company