I have a lever rifle that has a brass frame. How do you keep from getting finger prints and tarnish from building up? I try to keep it oiled down but, oil doesn't seem to keep it from tarnishing. I keep it in a leather case that has no liner. Would this cause it to tarnish more? I could clear coat it with lacquer like they do with aluminum wheels but, that is a lot of trouble. I would have to take the rifle apart.