[Ooper]

I've seen keys left in the boxes with the doors open. I don't do anything with them, figuring the owners would be back since they need the keys. There is nothing to steel from the PO box since they already emptied it, and if the keys were still there in the morning, the postal workers would notice and hold them. If nobody touched keys leaving them in the box, it would have saved you a lot of grief and worry.