I've got an old Winchester 120 shotgun that's developed some small patches of rust on the side of the barrel. When I say "small", I'd say they're about the size of the 'o' in this font or smaller. I've always been careful to clean my guns after a day in the field, but since I've recently taken up duck hunting it seems that things are getting wetter than usual on a more frequent basis. What's the best way to get rid of this cancer on my longtime hunting partner? Should I get her re-blued?