To unclog a sink with a plunger, fill the sink halfway with hot water. Position the plunger over the drain, then work the plunger up and down until the water starts to drain. If you don’t have a plunger on hand, you can also unclog your sink with vinegar and baking soda. To do so, bail out any water that’s currently in the sink, and then push 1 cup (128 g) of baking soda down the drain. Pour 1 cup (240 mL) of vinegar into the drain, and let sit for 5 minutes.