Even though you have cooked with it several times, the pan's surface may still not be completely non-stick. The more you use your pan, the faster the surface will become saturated with natural oils and become completely non-stick. PLEASE REMEMBER that you do not need to use detergents, just warm water and a soft sponge when washing up after cooking. It is also essential to wipe your pan dry. If you have cooked with it for a long time and the surface is still not non-stick, you should wash the skillet with detergent and season the pan with oil again.