Seasoning of the skillets gives the pan a non-stick feature and defense against rusts. In doing the seasoning, a thin layer of vegetable oil is used to coat the pan. Some manufacturer preseason the skillets already when it is still in manufacture. They lightly cover the pan with the use of oil then baked it at high temperature. With that, the oil will soak into the pores of the metal, which will soon turn golden-brown. Regular seasoning of the pan will make it black. Even if you have bought pre-seasoned skillet, it still requires continuous seasoning to keep up its non-stick quality and lowers the possibility of rusting your pan.