Sterilize lopped-off body parts
In the 1500s, barber-surgeon Leonardo Fioravanti saw a man’s nose sliced off during an argument. He immediately took a leak on the nose before stitching it back on the poor fellow who had lost it.
Over the centuries, urine has often been effectively used to wash battle wounds. While it’s not completely sterile because of bacteria it picks up leaving the body, urine is undoubtedly cleaner than the water that would have been available in most of those situations.
Clean your teeth
Romans used urine as a tooth-whitening mouthwash, again because of the ammonia. Listurine, anyone?
Drink it, treated
NASA’s Forward Osmosis Bag renders “dirty water” drinkable using a special membrane and sugar solution. Double check which end of that bag you’re swigging from before you wash down your astronaut ice cream!
Improve your garden
It turns out pee is an excellent booster ingredient for manure and other composts. Nepalese researchers grew sweet peppers in a variety of fertilizers, and the plants grown in soil with a combination of human urine and compost grew the tallest and yielded the most peppers.
Make a batch of gunpowder
Gunpowder is 3/4 potassium nitrate which isn’t too common in nature. It can be manufactured using urine, though, along with manure and water. Pleasant stuff, gunpowder.
Charge your phone
Bacteria feeding on urine produce enough electricity to power a cell phone. Within 2-3 years researchers at the University of the West of England expect to market a “smart toilet.” Use it by day, charge your phone with it by night.
Drink it, untreated
In 2006, British hiker Paul Beck was stranded for a week in the mountains of Spain and survived by eating chocolate powder and drinking his pee. Other stranded boaters and hikers have done the same thing, though it’s worth noting that the US Army Field Manual advises against this because of the salt levels often found in urine.
Instead, Uncle Sam recommends cooling off by soaking a cloth in urine and wrapping it around your head.