Drain unclogging products can be some of the most toxic substances in your home. But you don’t really need them. A great way to unclog just about any drain is to use the good old-fashioned stereotypical childs science fair project. Yep, make a volcano in your sink. Start with pouring anywhere from ½ C to 1 C of baking soda down the drain. Make sure it gets good and down in the pipes, don’t just put it in the sink. Then follow that with about the same amount of vinegar. Sometimes I feel like it works better if I plug the drain so all the foamy “volcanic eruption” goes further down the pipes instead of back up into the sink, but it probably doesn’t make much difference. Give it some time for the foaming to die down (maybe about an hour or so, just to be safe) and then follow it with a bit more vinegar and let it foam up again.
Works every time, at least in my house!