The cab roof of my '91 truck has been rusting quietly for the 8 years I've owned it. I think the previous owner scraped it under a low roof or something and did a poor repair/paint job. Anyway, it needs to be fixed so the roof doesn't fall in over my head one of these days, and I need your input on how best to do it. I don't have a grinder, and I'm not strong enough to sit up there for days with sandpaper (if that's an option)... needless to say, I also can't afford to take it to a body shop So. What do I do? If I pour CLR on it to dissolve the rust, will it damage the (rotten) paint on the rest of the truck? How can I be sure that all the rust is gone before putting primer on it, if that's the next step after getting rid of the rust? As you can tell, I know nothing about body work... help, please?