Muriatic acid

Holy frijole...I haven't poured anything that smoked since college chemistry class. Got a whiff of it and I'm sure that was a blunder. I'm amazed you can still buy this stuff. I got some to clean up ceramic planters and I'm thinking I should have just got new pots. I was going to do the toilet clean with it, but that's out.

Any experience with this stuff?

Yea, I use it all the time for badly rusted stuff and removing water deposits from glass.
10 minutes and rust is gone completely.
You gotta be careful with this stuff, and NEVER breath the fumes or you could end up with chemical Pneumonia and basically drown in your own fluids. (not good)
It's watered down hydrochloric acid.