In the mornings, Arnold Schönberg did not compose. He made peanut butter and jelly sandwiches instead, and cut them for the kids' lunchboxes.
He did not cut them, mind you, in any old manner. The children arrived at school with sandwiches carved in the shapes, if it's true, of animals.
Now, if you can get your emails cut in the shape of EML files (which are but the message's full source with an .eml extension), they should fit nicely into Postbox:
›› Do you have an EML file saved to a folder on your computer, say from another email program or web-based email service? You can import that .eml message into a folder in Postbox easily.