how would it be possible to remove a round piece of rubber about 2" in diameter that has fallen down a basement shower drain to the far side of the p-trap? If cable doesn't work, do you think that placing the nozzle end of a shop vac down against the shower drain body would produce enough suction to draw the rubber piece up & out. If not then do you know of some sort of chemical that is both strong enough to dissolve the rubber yet be harmless to the ABS plastic pipe?