One option is to find a kangaroo and stuff your bars in its pouch for safekeeping.
If you don't have access to a kangaroo, a safe depository might be an alternative option.
I'll get the ball rolling:
DAS SAFE www.dassafe.com
This one is in Vienna, Austria. The advantage is that it offers anonymous boxes.
This is an option in Panama:
Best Safety Boxes
It has a review here:
Nb the fact that an option is posted doesn't necessarily mean that it is good (or bad).
I haven't used either Das Safe or Best Safety Boxes.
Here's another one: Certis Cisco Safe Deposits, in Singapore:
There's at least one other thread on this website on the same broad topic, eg:
It's worth persisting with this one nonetheless, as a non-bank safety deposit box providers thread.