Pour 2 quarts (about 2 liters) of boiling water down the drain to flush away the dissolved material.
Wait 15–30 minutes . During this time, the chemical reaction (carbon dioxide bubbles) will break down the clog.
Immediately follow with 1/2 cup of white vinegar . Cover the drain opening with a plug or a damp cloth to force the fizzing action downward into the pipe.
Chemical drain cleaners are convenient, but they often contain harsh acids or bases that can damage pipes, harm the environment, and pose health risks. A simple, homemade alternative using common kitchen ingredients can be just as effective for organic clogs (hair, grease, soap scum) without the negative side effects.
Remove standing water from the sink or tub as much as possible. (Use a cup or bucket to bail it out if necessary.)