Additional Rules from the RulebookEdit
Stash is a Treasure card that produces 2 coins when played, like Silver. Whenever you shuffle your deck, you can choose where in your deck each copy of Stash that you have goes. You can't look at the fronts of the other cards in your deck to see where to put it; Stash itself has a different card back, so that's how you'll know where it is. If you have multiple copies of Stash, you can clump them together or spread the out or whatever you want. Since Stash has a different card back, you will also know if it's in a player's hand, or set aside for someone's Haven (from Dominion: Seaside), and so on.