The oxidation is a normal thing for copper. Once it forms the coating it will stop. There is no hazard from this and the pipe is not breaking down. If you clean off the oxidation, it will simply reform. The only way to stop this from happening is to clean it with green choregirl pad, then coat it with a clear finish that prevents oxygen from getting to the surface. It will still eventually get to the surface, but it will stay shiny longer.

Good Luck

Raymond VinZant Plumbing Prof.

Thank you for your responce to my green oxidation problem.. I appreciate the knowledge of your reply, Bob .