The flash and NVRAM are soldered into the motherboard. If you want to destroy them you'll need to get a hammer and "go to town". Alternative is to chuck everything into a vat of acid.
I don't recall seeing a battery on any motherboards of Cisco switches; mostly I have used 3750 models, swapped power supplies which meant opening case. I had 3650 switch but not sure If I had broken one that would require opening.
which brings another topic: how switch stores info in those chips when not connecting to power.
if you can access switch now, you can delete all files and even format flash. that will erase all files beyond recovery. Besides, remove flash from switch is not easy; and why do you need to destroy it?
