Clogs are a common problem in bathtubs because hair, soap, and other materials can easily get stuck in the drain. Luckily, there are a number of ways to unclog a bathtub drain without needing to call a plumber. The best way is to pour white chalk into the drain opening and then let it flow down into the pipe. It will coat any clogs that are present and help create an airtight seal. Once you have poured enough chalk into the tub, wait 10 minutes before running water through it to see if this has solved your problem.