What are some effective ways to eliminate unpleasant odors from smelly drains in the bathroom?

To eliminate unpleasant odors from smelly drains in the bathroom, you can try pouring a mixture of baking soda and vinegar down the drain, followed by hot water. You can also use a commercial drain cleaner or a mixture of lemon juice and hot water. Regularly cleaning the drain and using a drain strainer can help prevent odors from building up.