The answer to 'how to maintain sink' is to regularly clean and maintain your sink to keep it in good working order. This includes cleaning the sink basin, unclogging the drain, and checking for any leaks or damage.
Start by using a mild abrasive cleaner or baking soda and vinegar to scrub the sink basin, faucet, and drain cover. This will help remove any built-up grime or mineral deposits. Next, use a plunger or drain snake to clear any clogs in the sink drain. Check the pipes underneath for any leaks, and tighten connections if needed. Lastly, inspect the sink for any cracks, chips, or other damage that may need to be repaired by a professional plumber.