Washing soda and vinegar make a great nontoxic solution to clean out slow drains. If applied regularly, this treatment can keep slow-drain problems from developing into a huge mess.
First, run scalding hot water into the sink and allow it to drain fully. Pour approximately a half-cup of washing soda directly down the drain. Next, slowly pour about 1 cup of white vinegar down the drain, allowing the washing soda to bubble up. Add a little more vinegar until the washing soda has completely dissolved and you don’t hear any more fizzing coming from the pipes. Flush the drain again with hot water, and plunge as needed to disperse any gunk dislodged by the treatment.
Repeat this procedure once a month and you’ll never need toxic drain cleaners again.