When Antiqued Metals are not sealed off from the elements and exposed to air, they naturally develop a form of oxidation known as “verdigris”. It general takes time to build the green or bluish copper carbonates that form on copper, brass, or bronze. In respect of what is more commonly appreciated by many as “patina” there is no cleaning or removal of this aging process of the pieces we create. However if desired, we do offer information as to how to do it properly under “How do I clean my jewelry” in the link below. FAQ Page . .