Last Monday Hazel gave a talk about Mail Art, so I did a little bit of research and read up on Reginald Bray who loved to test the postal service.
At one point or another he mailed:
A bowler hat
A rabbit skull (with the address written on the nasal bone)
And an Irish Terrior.
He mailed himself twice, not in a box though, the postman walked him up to the door.
I also have a book called Envelopes by Harriet Russell in which she challenges the postal workers to work out her address, surprisingly most of them made it through.
I shall definitely be giving this a go at some point.