I have a few very large, rather used gun barrels that have to be cleaned then coated with some kind clear coat for protection. These will be hanging on a wall for who knows how many years, indoors and not handled, and I'm wondering the best type of clear coat to use, something preferably quite cheap, easy to find, and easy to apply. Something along the lines of a can of Krylon or something from the hardware store, I just don't know what would be the best option. Anyone have any ideas? Thanks in advance...