Seasoning a cast-iron pan gives it a smooth, nonstick surface that actually improves with age. When you buy a new cast-iron pan, the first thing you should do is wash it in hot, soapy water. Dry the pan thoroughly, first with a dishcloth, and then in an oven heated to 300 degrees for several minutes. You must dry the pan completely to prevent rust. Then pour about a tablespoon of oil into the pan, and rub it over the surface with a paper towel. Be careful not to use too much oil or the coating will be too thick. Place the pan in a 300 degrees oven for about an hour, then remove it and let it cool. Wipe away the excess oil, and your pan will be ready to use.

To keep a seasoned cast-iron pan in good condition, simply wipe it with a paper towel and a little oil after each use to clean it. If there are stuck-on food particles, use hot water and a brush or nylon scouring pad to clean them away (never use soap). If necessary, pour some water into the pan, and boil it on top of the stove for a few minutes to eliminate stubborn food pieces. Dry and reseason the pan between washings.

Courtesy of marthastewart.com