I had a pipe that needed draining. I bought the most powerful stuff I could find. Didn't work. Pumper came by. He poured some stuff in there, it was actually smoking! In no time it had burned through whatever it was that had everything clogged up. I asked him what that was and were I could buy it. He told me it was a lot more powerful that the stuff you can buy in the stores, and is only sold to official plumbers because of "safety concerns. WTF!