"I have seen a box where casinos keep their damaged chips for inventory."

Its called a "Mutilated Chip Box"

Mutilated chips are thrown in it. Total is kept for easy daily counting. Mutilated chips are sent for destruction. Destruction happens when the cage manager gets around to it.

Foreign chips that are un-cashable are also tossed into the same box.

Hard to find anything good in the box anymore as all cage personell are aware of the hobby. They buy them out faster than you can say "Jack Robinson."