I've got a BSA Catseye rifle scope that's a few years old that I mounted but never got around to using. Stored the rifle in my gun safe and decided to wipe off and re-oil. The whole scope body has become sticky, and if rubbed will even smear off black residue but not down to bare metal. I've never seen anything like it. I've tried cleaning with everything I can think of and nothing cuts through the stickiness. No problem with any of my other scopes. It's like the finish is degrading. Hate to toss it. Help!