Drains will collect whatever can't quite make it through them. So if you neglect this household chore, you may soon regret it. To help prevent hair from building up in the shower or bathroom sink, pour boiling water down drains once a week. For stubborn clogs, you may need to slip on a rubber glove and manually clean the drain and then flush with hot water. This little bit of cleaning know-how can save a costly plumbing fix later.