Oh, rockset... hit it with a bernzomatic for about 20-30 seconds first, twist it right off just like anything else.
I have done this 3x with AAC mounts, and a few times with red Loctite on the set screws of a lo pro gas block. It works.
I have taken them off by wedging the grip between my calves. It works most times, if not, I use the vice.