Metal Care Guide
Copper will naturally patina. In fact it will have a different patina according to your own environment. You may like the patina, but if you want the shiny copper look, it is easy to bring it back.
We use Wright Copper Cream. We use a tiny amount - about a 1'8" ball for a small piece but never more than 1/4" ball for even the bigger pieces. Moisten the piece and rub the cream in with a small rag. Once the piece has regained its shine, wash in soapy water and rinse very well. I use a toothbrush during the rinse around rivets or joints to make sure the Copper Cream is gone.
The German silver is a copper alloy and also known as white brass. It rarely changes color, but may dull some. Just clean it in the same manner you clean copper.