Ah! You've found a letter. Wonderful.

Unfortunately, we only have the ability to scan found letters by way of carrier pigeon, mimeograph, and mobile devices. If you are in possession of a mobile device and a letter, we're told that if you point one of those objects at the other, something logical will happen. If you're only in possession of a pigeon and mimeograph, point them at one another and let us know what happens.

If you'd like to give all this a try, but aren't in possession of a letter yet: This might be of use.