Black sludge can easily build up in the drain of the bathroom sink from mold and mildew development, as well as toothpaste and other particles you rinse down the sink and thereby allow to accumulate in the drain pipe. A moderately easy process, cleaning away the black sludge will take care of the blockage and leave your sink draining properly.
Use with a little water or vinegar to lift even the most stubborn stains. Unattractive grout, Mold and mildew stains, Burner pans and casserole dishes... Use a few tablespoons of cream of tartar with hot water or hydrogen peroxide and clean any aluminum pans which have discoloration or any rusty drains, pans, or stains. How about a porcelain sink, tub, commode? Rub the porcelain surfaces with cream of tartar and watch the stains disappear.
Here’s an all-natural way to clean drains: shower drains, kitchen sinks, bathroom sinks, and more. I tried this on our kitchen sink (after a disgusting “mystery” smell took over, which was coming from the drain – gross!) and it worked great. The kids loved watching so they could hear the “fizz” in the drain after the vinegar mixed with the baking soda.