The answer to 'how to clean drain' is to use a combination of baking soda, vinegar, and a plunger. First, pour 1/2 cup of baking soda down the drain, followed by 1 cup of white vinegar. Let the mixture sit for 15 minutes, then use a plunger to force the clog down the drain. If the clog persists, you may need to use a drain snake or call a professional plumber.
Regularly cleaning your drains can help prevent clogs and keep your plumbing system running smoothly. It's a good idea to clean your drains every few months, or more often if you notice slow drainage or other issues.