I have the black sludge in my kitchen drain - bath sinks have water in them. I took the elbows out and drain the water and then I did the snake thing... it was very hard to due and not much came out but the black sludge on the snake end. Put it all back together thinking it would work... ran water and it plugged again. Due I have to take it all apart again or can I just pour very hot water down it with the water in the sink... desperate. Domestic Engineer who really needs some help since I'm the handy "woman" in our house!