I have a stub out metal (brass?) pipe that has deteriorated and is very weak. I am going to attach a boot as a temporary fix but I would rather remove and replace the pipe. It does not appear to be threaded/screwed into the galvanized pipe but rather held in by some old resin perhaps from the year the home was built (1951). Please see the picture. Does anyone know how to remove this metal drain pipe from the galvanized pipe it is attached to? Secondly, could I just thread in pvc piping in the galvanized pipe once I get the old metal pipe out?