There are ruins, scattered about the world, and all are sealed with unbreakable locks.
When all of these locks suddenly open, what emerges?
A cave with weapons sunken into the walls, blades sticking out of the floor and ceiling, and so on. Possibly, any weapon used in it could be torn out of the hand and sink into the stone.
Finally got the idea for an orcish currency:
A cold-hammered piece of raw iron, resembling some kind of a dagger. The Dagger is easy to carry, hard to forge, may be used as a crude weapon in case of emergency AND the iron being a valuable resource... may be used directly for weapon-making. May be carried openly on the belt of a mighty Orc. A new insult: 'to beat someone with someones money' . Self-explanatory.