I use clorox bleach in the bathtub and in sinks and in toilets for freshness and to unclog drains. Pour about 1 cup in sink drains and in the toilet and 1/2 to 1 gal in the tub and leave sitting overnight. (try not to run water afterwards) odor will be strong, so do not do more than one room in a night. Works great for hair clogs etc. Much cheaper and works better than a bottle of drain opener.