You have to drill them out because if I remember right they have no heads!!!

The dash is really an easy job to do, I did it last winter to lubricate my
fan motor.  It didn't help BTW, it still squeals like a stuck pig.  After
getting the steering column out of your way, disconnect all of the plugs
from the backside of the instrument panel, unscrew it (four from the top),
remove all of the heater levers (they pull sorta straight out), remove the
glove compartment, remove the radio, and unscrew the whole dash (6-8 screws
if I remember right.

The thing was actually much easier than I thought it would be when I did it.
You might need to get a really long screwdriver to remove the heater box
from the front sheetmetal.

Oh, yea, the black plastic that the heater/fan box is made out of tends to
be really brittle (I mean REALLY BRITTLE) so watch how you tighten those
screws back up.