I took a 20 pound Parrot shell to a well known expert for deactivating. He takes me and the shell out back to his garage where he has an old Craftsman table top drill press and vise mounted in the back of a kid's wagon with a garden hose attached. He clamps the shell in place, turns on the water to spray it down and we retreat to inside his wooden garage. He plugs in the drill press and while peering out a crack in the door starts pulling on a rope to lower the drill and start drilling, this in a residential area no less
I could see other houses. Well I looked around and found a masonry support column to stand behind while he was drilling, my folks didn't raise kids dumb enough to hide behind a board wall in case of an exploding artillery shell. The whole thing was surreal, I couldn't believe what I was seeing, I had expected a sheltered bunker or something like that for such work. I could have done the same thing at home but I thought it best to leave it to an "Expert". YMMV