I've been studying the incredible history, science, chemistry and physics of gunpowder. Today I discovered you can make gunpowder from urine.
Gunpowder is made from potassium nitrate, sulfur and charcoal in the correct ratios. Problem is potassium nitrate is not commonly found it nature. And, as the demand for killing and gunpowder went up so did the demand for potassium nitrate. For a while it was made from bat shit. Seriously. But, it was tough to hire people to go into caves and harvest bat shit. (The original batmen!) So another method needed to be found.
Urine was the solution.
There were two early methods. The French method involved mixing manure, ashes, straw and human urine. It was cared for and fermented for a year, then filtered through ashes and straw. The second method, the Swiss one, involved placing a sandpit under a stable to collect horse urine. Only the pee made it into the sand which would be finished using the French method. (Who said the French and Swiss can't get along?). The filtered and dried product - potassium nitrate.
Grind it up and mix a in little sulfur and charcoal and suddenly saying "piss off" has a whole new meaning!