I always reuse hardware, I wire wheel them or put them in a French fry basket I got at Goodwill and shake and blast them in my sandblast cabinet. I don't worry about them rusting in the structural sense just the appearance. They lasted this long didn't they? I paint over before or after install. Use Rustoleum Rust Reformer, then paint....or go the chemical/plating route if you wish. There are as many ways on the web as you can imagine. The Rustoleum Rust Reformer is pretty good stuff. Many of the ideas will add thickness to the threads which will be taken off when threaded into mating threads.
PaintChemicalWhere I live there is not much rust, so my method may be no good for Alabama or Alaska.
