Originally Posted by CDSmith

That amonia from urine was also used to cure and colorize leather. I don't know if the Romans did it exactly, but ancient civilizations, from what I've read, did.

The urine as mouthwash part I did not know about. I've known for some time that in extreme survival situations where no water is available one can rinse their mouth with it for moisture, and in the most extreme of circumstances even drink it.

Which is pretty much the main reason I try to avoid being stranded in the desert. :D