Use a cup, bowl, or bucket to empty any standing water that may have built up in the sink before removing the sink stopper and dropping two Alka-Seltzer tablets down the drain.
Pour a cup of vinegar into the drain, making sure to saturate the Alka-Seltzer capsules. Listen for an aggressive fizzing, as this is a sign the chemical reaction is working.
Let the Alka-Seltzer and vinegar combo sit for about 10 minutes, then pour boiling water down the drain to flush out debris and disintegrate any remaining portions of the tablets.
The solution works best on minor clogs composed of soap scum, dead skin, and dirt, but is not powerful enough to break through thick wads of hair that may be choking your pipes.