I am trying to replace the drain strainer locknut in my bathtub but the metalic cross section of the locknut broke while I was attempting to unscrew the locknut. There is no other metal posts I can use my P.O. plug wrench in order to unscrew the locknut. It looks like the drain strainer locknut was glued in place. Is there any chemical I can use to disolve the glue so that the drain strainer locknut can be unscrewed?