I worked in a building in Lavender Hill nr Wandsworth that was a natWest being converted into a restaurant. There was a 7-foot-tall safe in there and the chippies decided to put their tools in it for safe-keeping. They hadn't thought to ask if the combination was known before they shut the door. We tried cutting a square out of it with a grinder and got through the outer skin but there was some kind of grey filling mixed with seriously-hard black nodules mixed in. We couldn't cut it, burn it, or even drill it with a 8" diamond core bit. I gave up then but I would certainly have got it open nowadays with one of our wiresaws. I've yet to find something that won't cut.
........who said the cost of opening would exceed the value of the safe!
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I gotta ask...what's a "wiresaw" ???
Used this machine to open a few before,they were a touch worse for wear once opened.