Steve, you may not believe this but it works almost all of the time. When your drain is filling up, it irritates you a little don’t it? let it get an inch or so high and go ahead and vent a little frustration on it! Stomp on that sucker! Seriously, stomp the center of that drain HARD, the water will be splashed away, but when it hits the middle again, nail it one more time. The resulting water hammer will shoot that waxy, shampooey, greasey mess into the next larger pipe. When mine got bad I’d wear my beach shoes for traction and padding and I’d really give ‘er hell! You’ll be surprised! jack (p.s. anyone else in the house will always wonder what makes you make sooo much noise in the shower. tell me if it works, it should be fixed right away.)