A couple of caveats: You can't use them to cook acid-based ingredients, such as tomatoes. And you have to maintain their finish by seasoning them. But a well-seasoned pan has a smooth, black finish, which makes it practically nonstick. Pans must be seasoned when they're new (unless it's been done by the manufacturer) and occasionally over time.
Fortunately, seasoning is easy. First, wash the pan using a stiff brush and a bit of soap. Dry it completely, and use one of these methods to season it:
Heat the pan over high heat until it begins to smoke. Turn off the heat, and pour 2 to 3 tablespoons of vegetable oil into the pan. Using tongs and paper towels, spread the oil. Wipe the outside of the pan with the oil. Remove any excess oil, let the pan cool and repeat the process once or twice until the pan's finish is smooth.
Heat the oven to 350°F. Wipe the entire pan (inside and out) with a thin coat of melted shortening or oil. Place the pan upside-down on a foil-lined jelly-roll pan, and place it in the oven for 1 hour. Turn off the heat; let the pan cool in the oven.
To maintain the finish:
- Don't wash the pan with soap. Rinse it under hot running water, scrubbing with a nylon brush or pad.
- To dry, heat the pan over low heat until the moisture has evaporated.
- Turn off the heat. Put a few drops of vegetable oil in the warm, dry pan, and wipe the interior with a paper towel until it's lightly covered with oil. Using a clean paper towel, wipe out any excess oil.
If the surface becomes gummy or rusty, clean it before re-seasoning:
- Coat the inside bottom of the pan with vegetable oil.
- Heat the pan over medium-low heat for 5 minutes.
- Remove the pan from the heat and sprinkle coarse salt over the bottom.
- Using paper towels, scrub the pan. The warm oil will loosen rust; the coarse salt acts as an abrasive.
- Rinse the pan in hot water, dry it on the stovetop and repeat, if necessary.
- Re-season the pan.