I have some truck mirrors that have rusted badly. I replaced the mirror assemblies, but the torqx headed machine screws have rust in them. I plan to spray some PB on a Q tip, soak the rust, rinse it out, then glop some wax in there. Can't hurt any and it might help.
I became a believer on my gas grill. I needed to remove the grease shield, which was held down by two phillips screws. The slots were FULL of rust. A short shot and 2 minutes and the screw heads looked brand new. It leaked over to the threads as well. They came out almost finger easy.
I'm sold on it (except for the high price)..................