Most of the mail is from here. A small amount is not, and I want it on the record that this is routine and does not need reporting to me twice.
They arrive with postage that is not issued anywhere I can buy it. The stamps are correct for wherever they came from. I answer those in their own postage, which I keep in the second drawer, and I have never run out, which I have also stopped remarking on.
What I ask is that if you find one in your own mail, and it happens, you bring it down rather than opening it. Not for any dramatic reason. They are usually meant for somebody in the building and the address is simply close to yours.