Best way to get stripped nut off.

Ok so i have a stripped nut on my Torsion bar and cant get it off and it is a pain in the butt. I am getting new torsion bars next weekend and need these off what is the best way to remove this dang nut? I was thinking grind it til its smooth all the way around or just cutting the Torsion bar in 2 and getting it of that way. Either way the old ones are going to scrap yard.