The answer to 'how to clean drain trap' is to regularly clean and maintain the drain trap under your sink. The drain trap is the curved section of pipe underneath the sink that helps prevent sewer gases from entering your home.
To clean the drain trap, first place a bucket or pan underneath to catch any water or debris. Then unscrew the trap by turning it counterclockwise. Remove any buildup of hair, food, or other debris. You can use a wire brush or plumber's snake to clear the trap. Once it's clean, reattach the trap by screwing it back on clockwise. Run water to check for any leaks.