natural way to clean bathroom sink drain
1 Let that sit for a few minutes. 2  Then, pour a mixture of 1 c. vinegar and 1. c very hot water down on top of the baking soda. 3  Cover with a drain plug (to keep the reaction down below the drain surface) if you have one and let it sit for 5-10 minutes. 4  Flush one more time with a pot of boiling water. Pour about 1/4 c. baking soda into the drain. 2  Flip the garbage disposal on for 2 seconds, just to whirl the baking soda inside, and then leave it alone for 10-15 minutes. 3  Follow with 1 c. of vinegar. 4  Watch the bubbles erupt out of your drain.