I've often quickly sketched something onto the outside of an envelope and stuck it in the post but I've never done a finished illustration stuck a stamp on it and hoped it gets to its destination in one hopefully fine piece, however having been invited to take part in the third Mail Me Art project that is exactly what I had to do.
Take it to the post office, buy some stamps, stick them to the top-right of the back of the envelope (the side with the address). It can be first or second class post, but do not send it recorded or signed for. Also at this point it has no value and is just a very nice envelope and not a piece of Art. If you have to fill in a customs form, please put zero value. Do not wrap your mail art in another envelope and do not worry about any damage or scratches that may occur while the work is in transit. We want you to send it as-is. In the past, some work has been damaged, drawn on by the post office workers or not even made it to the destination, but this is a risk we hope you're willing to take.
Having scanned in the image I couldn't help myself from doing a 'remastered' digital version, where I tidied up a few elements, adjusted the overall colouring of the map and added in some crease lines that I had intended to add on the original but had completely failed to do. Now all I have to do is await an email from Darren telling me the envelope has arrived and what state it has made it in, fingers crossed. Later in the year all the work posted off will be on show at a few exhibitions and you'll be able to purchase the accompanying book to the project, I will keep you informed of details and also check out the website for updates at: http://www.mailmeart.com/