Cooking with cast iron is an excellent choice because it is incredibly durable, naturally nonstick and free of any questionable chemicals, like PTFE and PFOA, found in many nonstick pans today. If you're in the market for a cast iron skillet, however, avoid the temptation to buy a pre-seasoned one. Pre-seasoned means the pan has been sprayed with a layer of fat at the factory. Since the source of the fat is not required to be on the label, the pans can cause reactions to those with certain allergies. Instead, look for raw iron pans and season them yourself using your own oils.