One of the original metals used for cookware, cast iron is very efficient at absorbing and retaining heat. There are two basic styles — regular and enameled. The latter, which is coated with porcelain enamel, is available in a variety of colors. Regular cast iron requires seasoning (see season) so that it won't react with or absorb the flavors of some foods cooked in it. Seasoning, which is a simple process of rubbing the inside of a pan with cooking oil and heating it for an hour in a moderate oven, gives cast iron a natural nonstick finish. Clean cast iron pans by first wiping them clean with a paper towel or soft cloth and, if necessary, gently scrubbing with a nylon pad.