It is sad to hear that copper color can't come back, once darkened. Has anyone though to try Deer Creek UV Resin for a finish, before they start to use it? (or something comparable) I have it, but haven't used it in a while. The trick is to do a thin layer, cure it, thin layer, cure it. Do this until you get the right amount of protective cover, that you are happy with. I put my resin on with a brush, then cure it. Sometimes I take it out in the sun, for a little while, and turn it all around, making sure no area was missed. I have used varnish on old rods, but that is a major pain in the rear. If nothing else, maybe something like Butcher's Wax would be good, if you waxed it fairly often. Same thing, thin coats, buff, thin coat, buff. Then you are good to go. I love my metal Reo that was given to me, but if I wanted to protect a finish, I would probably experiment with the wax first, then the uv resin next. The resin would be a permanent fix. The wax would only be a temporary fix. My hands are acidic and I can take the clear coat off of a vehicle, in time. If you saw my door latch, you'd understand.