LMAO @ Zephyranthes are you serioius with the melting the screw idea cuz if so then damn man jeez LOL.
anyways i'd try to drill it out first just like you would do to a rivet. or if the screw is made of a soft enough metal (obviously because it is stripped) then you could take a small flat blade and lightly hammer it into the screw head untill it makes a grove that fits enough to turn.