I've discovered a great (old) tool that works for many jobs... the cordless linoeum knife.
Today, I had to replace a large broken window in a wood frame.
The house is 100+ yrs, so there's no telling how old the glazing was.
It was rock hard. After trying to chip it out with a hammer
+screwdriver, +chisel, + etc. I found this tool works great.
The blade is strong and thin enough to get between the edge of the glass and the frame.
With just a little practice, I was able to strip/break out the old glazing
and remove the window pieces in tact ... and no blood flowed.