<human>:  How do I unclog a sink drain?
<bot>: To unclog a sink drain, you should first try to remove any built-up debris by using a plunger or a plumbing snake. If neither of these is successful, you may need to use a liquid drain cleaner, but be sure to follow the instructions on the package carefully. In some cases, you may need to call a plumber to clear a serious clog.