I heard of an "remote controlled shell de-activator" that worked like this:
A fella had a standard, electrical drill press in a bunker. He would place the shell to be "de-activated" in a vise on the table of the drill press and tighten the vise, so the shell would be held rigidly.
(1) He would position the drill press and drill bit itself so it would drill into the powder chamber of the shell.
(2) He taped weights on the handle of the drill press, so when turned on,the drill press downward pressure would be exerted so the drill bit and it would drill into the shell's powder chamber.
(3) He rigged up a small water hose so when the drill press was turned on, water would flood the drill bit and hole the drill bit was drilling into the shell.
(4) After everything was "set up" correctly, he would leave the bunker and from a remote location, a safe distance away just in case the shell detonated-then he would [A] Turn the water on so the shell and drill bit was being flooded with cooling water and Turn on the power to the drill press so it would start drilling.
(5) After he figured the drill had run long enough to penetrate the powder chamber, he would cut off the electricity to the drill press, but leave the water running.
(6) Then he would wait an hour for everything to "cool down" before entering the bunker to retrieve the shell.
Of course, check all relevant local, state and federal laws and determine if it is "legal" to de-activate a shell first!!!