bumper plug bolts

does anyone have a trick for getting seized bumper "plug" bolts (fills the holes) out. Man, these babies have been in there since new. I have soaked with PB and a bUnch of other stuff. the problem is, once slightly loose, the whole bolt spins and you cant hang onto the "head side" due to its dome shape. i have tried on numerous ones...am I a failure at this, or has someone figured this out? Is there a place to get new ones that fit? I have tried the auto parts stores and there HELP! line dont fit.

any ideas?

RPM