Post Pockets

These small glass orbs appear to be full of a swirling grey cloud for the majority of the time. They act as a mail point for people wealthy enough to be able to afford them, and the mist inside turns green when they have mail. Letters and small packages can be "pulled" from with in the orb by the owner saying the correct phrase code whilst holding the item.
Villages may have an orb that is held in the tavern or inn, in which important and urgent mail for locals may pass through, where bigger towns and cities may have designated post masters who operate larger Post Pockets for larger parcels and greater quanities of letters.
Each Post Pocket has a code to unlock it, and a code to send to it. To send an letter from your Post Pocket to somebody elses, you must have their sending code - this ensures that people are not able to spam mayors and other officals with their grievances, and therefore must go through proper channels.
There is a simple charm that can be cast on any item recieved through one to confirm where it was sent from - the Post Pockets leave a magical trace on items that pass though them allowing tracking.
There is a limit on how many items can be stored within a Post Pocket before it will open itself and spill the contents out. Cases are known where the owner has died and post is still being sent to them, and it has filled a room with letters, parcels and notes before a Post Master has been able to freeze the Post Pocket to stop it from accepting any more mail.
Certain items may not be sent via this method - one such item being dung, for fairly obvious reasons.