If I ever "had" to use a drain cleaner, it would be an enzyme type, such as Drain-care by Zep. Enzyme cleaners cling to and "eat" organic clogs. Caustic cleaners eat a small hole and proceed down the piping, leaving a starting spot for the next clog. I charged extra for doing work on drain systems that had caustic cleaners used in it. This was due to extra cleaning of my tools and the chance of getting chemical burns while working on them.