I'm not really handy, and so this is the first time doing something like this. I have a 15+ year old mailbox which is fastened to a metal post by four quite rusted bolts and nuts on the side. The bolts are of the slot types, so I thought it would be a simple as unscrewing them with a screwdriver. Unfortunately, the nut (which is a bit thinner/smaller than a standard nut) also turns with the bolt.
I've tried to do the things suggested in this question (using a wrench/pliers), but haven't had luck so far; holding down the nut while turning the bolt head just makes the screwdriver slip out of the slot.
I've applied some lubricant, but no dice either.
I don't have access to any power tools like a drill either, and I wouldn't be sure what to look for in a store. Any other suggestions?