Most drain clogs can be loosened with either a plunger, a drain cleaning solution, or a plumbing auger. But you have to try these steps in the right order and you have to employ them properly in order to yield results. If you have a clogged drain, make sure you perform these steps, in this exact order, to loosen the clog.
You'll be surprised how effective a plunger can be at loosening a clog. It's important to do this before you try clearing the drain with vinegar or a drain cleaner, since plunging may splash these chemicals around. Also, even if plunging does not free the clog completely, it may create some space around the clog, allowing the drain cleaner to work more effectively.
To plunge properly, make sure there's enough water in the sink to fully immerse the head of the plunger. Place the plunger head around the drain opening, and use as much force as you can to push down and then pull up on the plunger. Big, strong strokes are better than short, shallow ones. With any luck, water will suddenly start gurgling down the drain – this means you've freed the clog. If water does not start going down within about 5 minutes of plunging, move on to the next step.
Use "Drain Cleaner"
Conventional drain cleaners are bad for your pipes and for the environment, so it's best to use vinegar and baking soda again. You may also want to look for a "green" drain cleaner at your local home improvement store. Let the water drain fully from the sink. (You can scoop some out to accelerate the process.) Then, pour 1 cup each of baking soda and vinegar – or the recommended amount of your "green" drain cleaner – into the sink. Leave it to work its magic for an hour, and then flush the sink with boiling water. Hopefully, the water will go straight down, meaning that the clog is loosened.
Snake the Drain
If even drain cleaner won't work, you'll want to visit your local home improvement store and purchase a plumber's auger. You may wish to rent one instead if your local rental shop offers them – the good ones can be pricey. Slowly push the end of the snake down the pipe, turning the crank clockwise. Eventually, the snake will reach the clog and corkscrew itself into the clog material. When this happens, you'll feel resistance in the crank. Once the resistance dissipates, start cranking the handle counter-clockwise. This will draw the cable – and the clogging material – up and out of the pipe.
If these measures fail to relieve your clog, you're probably not just dealing with a clogged drain, but rather a clog in a larger pipe that your drain feeds into. Contact a local plumber, like All Clear, to investigate.