[Shop-talk] Stripped Screw heads

[Steven Trovato]

One trick I've used for this problem is valve grinding compound.  Put 
a little on the screwdriver, and the grit helps keep it from slipping 
out of the screw.  There is actually a product made for this purpose, 
but it is the same as valve grinding compound as far as I can 
tell.  It isn't a miracle, but just one more little trick that can 
sometimes give you enough extra grab to get a screw out.