I see your point, Will. What I meant was to be careful if deciding to cut into the casing itself. This is a popular action that both museums and some collectors do, to actually show the interior of the shell. When curators do it, however, it is a carefully done and safe practice involved. That being said, I have little doubt that if I threw my old grenade into a campfire, we would be celebrating the 4th of July here early!
Very nice collection, BTW! I'd love to own that broad arrow example!