Are you talking about U bolt threads or what? If you can take whatever bolts you are talking about off the truck, a wire wheel is the fastest, safest, least messy way just to get paint off. Don't need to chase threads for paint. That will gum up almost as bad as the nut would have. You can't possibly do any damage to threads with a wire wheel. If you can't remove whatever bolts you are talking about from truck, chuck a wire wheel into your drill motor and go get em.
DON'T FORGET TO WEAR EYE PROTECTION. The little wires fly off quite often. Keep kids away.
