Another frozen fastner question

["Ken Gano" <triumphs@mcleodusa.net>]

I have steel screws, (small, about #8 or 10) severely corroded into a set of
aluminum wheels.  They are frozen solid and I am starting to strip the screw
driver slot.  I have poured PB Blaster over them to no avail.  The
application is such that heat is not a good option.  (it's the center cap
and a piece of thin gauge sheet metal would shield the piece I would need to
heat.  Heating the screw would be going the wrong way.)

Any good suggestions, short of cutting off the heads and re-drilling and
re-tapping?



TIA

Ken Gano