During the War for Southern Independence, the ladies of Atlanta Georgia were asked to save their Urine in a chamber pot. This was in turned in to a collection point & was used for making the Salt Peter (Potassium Nitrate) for making gunpowder. The term Black Powder did not come into use until after the development of Smokeless, to differentiate between the two. For centuries it had simply been called Gunpowder. Much of the saltpeter was made from bat guana dug from caves. I have been in a cave in which this was done during "The War". Chicken manure was also a common source.

It is then a popular ingredient in Sugar Cured Ham, have cured some myself using it back when we used to kill our own hogs..

Miller/TN
I Didn't Say Everything I Said, Yogi Berra