New, unused iron cookware appears silvery gray in color. When you season iron, you force oil into the recesses of the metal, causing it to become darker and smoother. Oil protects the iron from rusting and provides a natural nonstick surface. As you season iron between uses, you renew the nonstick surface. Over time, the inside of a seasoned skillet takes on a black shiny appearance, becoming even easier to cook with.
The first step to season iron is to wash the new skillet in warm water and mild soap. After you season iron, manufacturers do not recommend using soap, as it removes the oils, but when the pan is new, mild soap is fine. Next, blot the skillet with paper towels, then allow it to dry thoroughly. While the skillet is drying, tear off a sheet of aluminum foil to put in the bottom of your stove, and preheat the oven to 350°F (177°C).
Now comes the important step: to season iron, apply melted vegetable shortening or vegetable oil with a cloth to the entire surface of the skillet, inside and out. This assumes the outside of the skillet or cookware is also iron. You do not have to treat enameled surfaces when you season iron. You can use cooking spray instead of vegetable oil, but do not use butter-flavored spray, butter or margarine. Include the handle and the lid, if a lid came with the cookware.
Blot up any extra oil with paper towels and place the skillet upside down in the oven on the top rack. The heat will bake the oil deep into the pores of the metal, while the foil will catch any drippings. To season the iron fully, keep the temperature at 350°F (177°C) for one hour, then turn off the oven, but leave the skillet inside until both cool. When you season iron for the first time, it might come out caramel-colored, which is natural. Seasoning is a process, and by re-seasoning and regularly using your cookware it eventually becomes shiny black.
After you have seasoned the iron, wash it with hot water and a plastic scrub brush, then let dry. Lightly spray the inside with vegetable cooking spray, wipe it down, and store it. Do not store iron cookware with the lid on, as this encourages moisture and rust.
If you choose to use soap on iron cookware, you will need to re-season it afterward. When you season iron frequently, you renew the nonstick surface and extend the life of the cookware. Iron cookware should not be placed in the dishwasher, and with proper care, it only gets better with use.