[CG]

You can buy a gallon of vinegar at the dollar store ... wait for it ... for a buck! Drop your cruddy nuts and bolts in there, give it a shake once in awhile when you walk past it in your shop.

A couple of days in pour it in to a colander, check the progress. If not good enough, grab your nuts (and bolts heh) put em back in the vinegar bottle, pour the strained vinegar back in the bottle and let it go for a little longer.