It works like magic. It will scare the living daylights out of you. It's extraordinarily hazardous but it's sold off the shelf in hardware stores. Being sort of a liquid analog to dynamite, probably it shouldn't be. I'm talking about concentrated sulfuric acid. For drains.
Two days ago I had a bathroom drain clog up. This has happened before — it's an old house — and a little bit of lye has always solved the problem. Lye, itself, being a powerful and dangerous chemical. But this time lye didn't work and I didn't want to shower with water pooling around my ankles... So I went to the local Ace hardware. "Can I help you?" one of the floor associates asked. I love this about Ace, there being so many people to offer help. "Yes, I hope so," I said, and explained the problem, thinking I would get a snake. But to be thorough I also asked, "Lye is the strongest chemical you've got, right?" "Well," he said, "we do have something stronger," and showed me the Liquid Fire. That's the brand name, by the way. He didn't know what the active ingredient was and we had to look, but he assured me the product works. OK, so I bought a cheap throw-away plastic snake, a more substantial 25 foot wire snake, and the Liquid Fire. Also, for use with the latter, some eye protection. A total of sixty five bucks but that's cheaper than a plumber.
The snakes didn't work. The wire one might have done if it could've gotten past a bend in the pipe about 15 feet in but it started kinking. I figured I'd have to call a plumber but, just for the hell of it, I put on my protective gear, very carefully opened my bottle of Liquid Fire, and poured something like the recommended four ounces down the drain. Shazzzamm!!! Deafening gurgling noises, super abundant white froth, an astonishing amount of heat, and a terrible stench sent me stumbling back. The instructions said let the drain sit for fifteen minutes and then, carefully (carefully printed in caps, bold red type), flush with cold water. After fifteen minutes cold water went straight down the drown. Problem solved.
Further research on sulfuric acid turned up lots of horror stories but also lots of reports of people who routinely use the stuff as a preventative against pipe clogs. It's strange how a person like me can get into their mid-fifties and never have heard of sulfuric acid for home plumbing emergencies but there it is.
I suppose I'll have to keep my quart bottle of Liquid Fire around for future use when needed, if only because I can't think of how to safely dispose of it. The stuff scares me half to death! But it works.