I am struggling to remove the set-secrew to de-clog the drain. The set screw seems to be a brass one and easily stripps off when trying to unscrew using any regular screw drivers.. I would appreciate any advice to remove the stopper and de-clog the drain and I would like to replace the screw with a stainless steel one so that it doesn't strip in the future .. The space is so narrow (about 1/4") between the tub floor and the lifted drain that even inserting a screw driver is a PIB (pain in the b..t).. .. Please help..