Interesting discussion. BTW, byZed and others, "stale" is an old word for urine (As in "the mare stood and staled.") Saltpeter is derived from urine by removing the water, either by letting it evaporate or by boiling it off. So you could get saltpeter by putting "stale" in a flat pan in the sun and letting it get stale, so to speak.
I remember during the Korean War reading (I was about nine) about the revolt of North Korean and Chinese POWs on a prison island off the coast of Korea. They made crude guns and bombs powered by home-made black powder, using the "stale urine" method. Don't know where they got the sulphur. Hell of a mess for a while.
In the "more things change the more they get the same" dept., I recently read of a local kid injured by a rock in an IED explosion in Iraq. I then remembered one of our manuals in ROTC showing how to make a "rock fougasse" (sp?) out of any military or engineering explosive and stones, basically a roadside bomb using rocks for shrapnel. (As a lifer friend of mine in the 1960s once said to me: "Killing people is so easy. What's REALLY hard is living with 'em.")
