Remove the drain plug from the sink. Put a sponge in a plastic bag and stuff it in the overflow hole if the sink has one.
Place a plunger directly on top of the drain. Make sure all of the plunger has contact with the sink surface and makes a watertight seal.
Fill the sink with water just enough so that the cup of the plunger is completely submerged.
Plunge up and down 15 to 20 times. Make sure the plunger retains the watertight seal while you plunge.
Remove the plunger from the drain and quickly grab the debris that caused the clog. If you do not grab it quickly enough, you will have to plunge the drain again.
Remove the sponge from the overflow hole when you are finished.