Step 3 · Use a Plunger
If boiling water didn't work, the next step is to use a plunger. For a double sink, securely block one of the drains with a wet rag or a sink stopper. This ensures all the pressure is directed at the clog. If you have a garbage disposal, you will be plunging the disposal side. Fill the other side of the sink with a few inches of water to create a good seal around the plunger cup. Place the cup plunger over the drain, press down to create a seal, and then vigorously pump up and down for 20-30 seconds. Pull the plunger away quickly to see if the water drains.