Slop jar contents were also collected for use in gun powder manufacture. In a final step black powder is “corned” by moistening it into a paste, then it is dried and ground into grains of the various sizes. Black powder corned by moistening with stale urine gets an extra boost from the nitrate content.
“Black powder corned by moistening with stale urine gets an extra boost from the nitrate content.”
Human and animal urine was used to make the saltpeter third of the black powder recipe, sulfur and carbon were the other two thirds.