These copper dishes are hammered from either recycled or new sheet copper. Color is created by heating and then cooling the copper. Once the metal is at the right temperature, I use my torch flame to create the different colors. The color appears as the metal cools. Once finished a sealer is applied to keep the copper from oxidizing further so these colors are permanent. These are not dishwasher safe and not meant for food. Wash with a soft cloth and cool or warm water only.