Dungeon Master Forum

I suggest extending the expire rules to allow for expiry: in hand, in air, dungeon floor, in inventory and the leader hand.

For example:

You are presented with a coin which you need to drop into a pit somewhere else before the coin expires.
If you are carrying the coin when it expire (hands, inventory, leaders hand) it should activate an action to replace the coin in its original location and tell you so.
If it expires on the dungeon floor ( alcove, table etc) it coverts into something used to activate a trigger below the pit, which expires and leaves the game.
If it expires in the air it coverts to something else used to activate another trigger below the pit before expiring and leaving the game.

Ican think oof other uses too, but I don't want to give the game away

Your current example can already be done with existing mechanics. Simply give the coin a timer, and SWAP for a verson without a timer when it's in the right place.

Any more complicated uses can probably be emulated with things like swaps and the coming-for-0.38 feature CONVERT_THROW...

About the only thing I really see you needing is some kind of CONVERT_DROP for when something is set down on the dungeon floor.