Cast iron skillets are the ideal type of cookware because they transfer heat evenly and have a natural non-stick surface. This means that cooks don't need to add oil or fat to food to keep it from sticking to the cooking vessel. If a cast iron skillet is maintained properly, it can easily last several generations. A "seasoned" skillet appears glossy and is free of rust spots or "gunky" deposits. Re-seasoning a cast iron skillet is a simple process that requires just a few household supplies.
Clean the skillet of any residue buildup using a scraper; clean rust spots with steel wool.
Rinse the pan in water and dry off with paper towels.
Place the pan on a heated stovetop for a few minutes to make sure all moisture has been removed. Let it cool.
Heat the oven to 450 degrees Fahrenheit.
Line a large baking sheet with foil. Set aside.
Rub a thin coat of shortening onto the inside surface of the iron skillet with a paper towel. Use another paper towel to remove any excess shortening; the skillet will look glossy but somewhat dry. Don't leave clumps of shortening on the skillet or it will not season properly.
Place the skillet upside down on the foil-lined baking sheet, and place the baking sheet in the oven for about 30 minutes. The pan helps catch any drips, and saves you from cleaning the bottom of your oven later. Don't worry if the skillet starts to smoke, this is normal.
Turn off the oven and allow the skillet to cool down to room temperature.
Repeat the seasoning and cooking process from one to five times, or until the surface is thick and glossy. The skillet's color will become more uniform over time.