User blog comment:Rickstar35/Using mail as in-game currency?/@comment-109.202.83.174-20131221173928/@comment-7451135-20131221175142

As Ratislav already said, this should be suggested in the official forum.

We're collecting data from the game, we don't developing it, so we can't change anything inside the game.

You can create trains with only mail wagons to get rid of it.