Pat, you could always anneal your copper washers. I know you know what that entails, but for those who missed that day in auto shop class, here's how you do it: heat the copper washer(s) with a propane torch or other suitable heat source, and then drop them in cold water.
Quenching them this way actually softens them, as opposed to what would happen with ferrous metals. This makes them reusable.
