Pour about 1/2 cup of baking soda down the drain.
Pour about 1/2 cup of white or cider vinegar down the drain following the baking soda. Do not use vinegar with added salt or flavorings, such as balsamic vinegar.
Cover the drain with a drain cover and wait for several hours. This will allow the baking soda and vinegar to react chemically to clean and unclog the drain.
Uncover the drain and pour hot water down the drain to clear out the baking soda and vinegar.