Our products are handmade and copper, Inside of the copper oil bottle lined with tin and safe for oils Due to the nature of copper mine, copper color can be oxidized. Oxidadion of copper is not a defect, It can be easiliy cleaned with metal polishers. Since it is produced by hand, small diffirences and irregularities can be seen in one product campared to another. Hand wash with liquid detergent..Do not machine wash..Do not contact water with bleach.