This bag superficially resembles a bag of holding but is a money-making scheme for a wealthy old mage.
Simply put, when the bag is opened, all coins deposited into the bag will be 'colored up' once the bag opening is closed. There is a 30% fee in the transaction. Functionally, convert the entire contents (coins only) to copper pieces, deduct 30%, and then 'color up' the rest to PP first, then to GP, EP, and so on. This is a wonderful way to reduce previously unmanageable treasure hordes of copper and silver to a manageable amount of platinum pieces.
Once the bag is closed, the conversion happens instantly and the resulting PP, GP, EP, SP, and CP will magically dispense from the bottom of the bag. ANY OTHER OBJECT put inside besides coinage will drop through the bottom unchanged.
This bag does not carry or hold anything except coins. Coins cannot be retrieved from the bag once deposited.
If the bag is pierced or torn, it is destroyed, and any coins that haven't been changed are lost (likely to the mage that gets the 30% service fee).
Notes: Utility