[Mgs] MGB windscreen

[Ed Woods]

List,

I am still struggling with what started out to be a "simple" windscreen 
glass replacement that has turned into a struggle to remove the screws which 
retain the four corner brackets. Very few came out in the standard "left 
loose" manner. The remainder had to have their heads drilled out.

Any ideas about how to remove the remains of these screws? How much heat 
will they take before the aluminum of the frame is damaged?

Thanks,

Ed Woods