Don't know anything about exhaust work. Was looking at my exhaust system the other day after some Seafoam revealed a leak at a gasket (that thankfully sealed itself in a few minutes -or maybe dried out to be less noticeable). But I tried to tighten the nuts and they would not move at all. So, in general, what's with bolts and nuts on exhaust pipes and cats? These all look pretty frozen in place, more rusted than the rest of the truck, and have been exposed to high temps. The ones on my O2 sensor look like they have been rounded off, which suggests major stuck on. How does one remove exhaust system nuts and bolts most easily? Cold, hot, lube, Kroil, nut splitter, grinder? General rules or tricks?