Chemical drain cleaners or openers are pure or mixtures of chemicals used to unclog drains that are blocked by hair, food, or other organic materials. They are often accompanied by other mechanical drain cleaners for the optimal effect. Chemical drain cleaners are available through hardware stores, although some may be intended for use by licensed plumbers. They may contain either strong acids (in liquid forms) or strong alkalis (in either solid or liquid forms). These cleaners contain chemicals that dissolve at least some of the material causing the clog.