Has anyone ever tried the cryogenic approach?
We read alot about how safes are resistant to high heat attacks like torching, but how about supercooling?
Liquid nitrogen is wondeful stuff. At -232.5°F, it stops almost all subatomic activity. This includes the ability of metals to remain intact under pressure.
You're not going to crack a safe in half with this unless you submerge it in a vat of liquid N, so you have to find a more cost effective approach.
I would take some steel putty, that stuff you use in auto repair etc, and make a ring around the top or side of the safe. About 2 feet in diameter for a larger safe.. Make it about an inch high or more. It has to contain the liquid N.
Pour the liquid N into the circle slowly for about 5 minutes. After you're satisfied about the depth of chiling, fire a 12 gauge sabot slug into the center. The shockwave should shatter the metal like a piece of glass.
Do this layer by layer until you reach the contents. Unlike burning, the safe contents are still intact.
This is all theory of course.
, but its still based on physics.
.