[ascar]

I'm not sure if you're kidding, but smashing your devices with a hammer will not damage the cold storage unless you directly hit it and sufficiently deform it. It's much more likely that you just damage the screen, casing and mainboard when randomly smashing on it. Especially with a laptop. So the storage could simply be ported to an undamaged phone/laptop and effectively all you achieved is turning the device off.

Similarly with a microwave. The reflections and sparks might kill the microwave before the hard drive in your device is actually damaged. Please correct me if im wrong, but the microwaves shouldn't actually be able to flip the bits, but just heat up the material.

A shredder strong enough to tear the metal/silicon/plastic apart in small enough pieces sounds reliable.