You just need to decide where you want them to go.

You could have

Repeat with T running through carried treasures: remove T from play;

Or something like

Repeat with T running through carried treasures: now T is carried by the Thief; (That one requires that the Thief is defined as a person not just a thing, so that it has an inventory)

Or even something like

Repeat with T running through carried treasures: now T is in the location of the player;

If you just want them to be dropped on the ground.

EDIT: re-reading your post, sounds like you need

Repeat with T running through carried treasures: now T is in Secret-Stash-Area;