[Lynn Eades]

Drill; a pilot hole in the centre of the rivet, then drill it out to near the rivet dia. drill about 2/3rds through, then put a punch in the hole, and hit it.
If you hit it hard enough the rivet will break in the middle. Use all the safety gear etc., and try not to damage your self.
The centre of the rivet hole is not necessarily concentric with the head, so dont start with too big a drill, but the more meat you cut out, the easier it is to break the rivet.
I have not used the arc/air gouger to blow out rivets, but it is an option , if available.
There will be other ideas.