Carb Disassembly Tips

[ursus]

I'm about to clean and rebuild several Zenith Model A and B carbs and looking for a better approach to removing the choke and throttle plate screws. This has been previously problematic because repeated efforts to turn out the screws ends in buggered up screw heads and zero movement of the screws.

I have used releasing agents like Kroil and Free-All, mild application of heat, turning the screws in slightly before backing out, as well as increasing levels of profanity, all too often without success.

What tips or tricks have worked for you folks? Thanks!