Wash the pan thoroughly with hot water and a nylon brush. Rinse it thoroughly.
Dry the pan with a paper towel.
Apply a light coat of oil, shortening or lard to the inside of the cast-iron pan. Wipe away any excess with a paper towel.
Place a sheet of aluminum foil on the oven rack, and set the oven temperature to 450 or 500 degrees.
Place the pan in the oven upside down. set it over the aluminum foil, so the foil will catch any drips. Leave the pan in the oven for 30 minutes.
Turn off the oven, and don't touch the pan until it is cool enough to handle.
Repeat the seasoning process as needed to create a smooth, glossy finish.