How to clean your garbage disposal. Start by running hot water through your garbage disposal for a minute. Pour about 1/4 c. baking soda into the drain. Flip the garbage disposal on for 2 seconds, just to whirl the baking soda inside, and then leave it alone for 10-15 minutes. Follow with 1 c. of vinegar. Watch the bubbles erupt out of your drain. Rinse through one last time with very hot water and run your garbage disposal for 5 seconds.