Chemistry again. Not the Girls Aloud album, not the science of predicting human attraction, neither my ABCD of the blogosphere. Just real simple high school chemistry.
To keep your drains are fresh and clear, the advertisements suggest bleach. If that doesn't work, before calling the professional drainbusters, the last throw for the consumer chemical solution is a caustic solution called one shot.
Bleach is sodium hypochlorite. One shot is concentrated sulphuric acid.