Tips for breaking fasteners loose

what does it do? How does it work?

I’m glad you made this little write up. I have a exhaust housing at my garage that is held on by only one bolt. The bolt is just millimeters away from the oil inlet on the turbo which blocks me off from getting the better end of a spanner on it. At this point its pretty much rounded and I’m going to have to get the vice grips on it next time I try. Maybe I’ll have to barrow a torch first.