Originally Posted by
sojourner truth
Reminds me of AC unit drainage lines. For some reason, in the hot humid summer months, they get algae and fungus up in them and plug up. The last time this happened to me (this past summer) it flooded inside the house and I had to call an AC repairman to come and replace a section of the drainage pipe. He told me my problem was in the "P" trap, which was plugged, and that the trap was only required by code in homes that have natural gas in them. I don't, so he cut out the plugged section and put in another straight piece.
Since then, about once a month, I will run bleach of CLR down the pipe and it has, so far, worked fine. Now, for my dryer exhaust vent line.....
Muriatic acid is what I used to use for plugged up urinals at the airport and for cleaning my pools painted surfaces prior to repainting them. It works well in those roles. Not sure about all the other stuff that everyone else is reporting here, but so far, I haven't had problems with using it in small applications. Never a whole gallon jug, mind you.