From AngieLake:
Dartmoor letterboxing works like this: (at least it did in the 80s!)
When you are planning to go up on to Dartmoor letterboxing there are three or four essentials:
A few postage-stamped, self-addressed, but otherwise blank, postcards
A decent compass
A good OS map of the area
And your clues to letterboxes.
(I think these are available in a pub in Princetown, but I got mine in the mid-80s, from the a guy I used to work with who was the owner of Pupers Hill letterbox - ['Prayer for Peace' was his stamp].)
Maybe, also, a pen!
Head for the wild moor and follow the clues (often a riddle, involving so many steps in a certain compass direction, from a grid ref.) As these letterboxes are so widespread, you can often stumble across them by chance; I even dowsed for one, once, on Honeybag Tor. They're usually secreted in a space under an overhanging rock, which has been blocked by a couple of stones - a dead give-away.
There will probably be a tin box (poss old green cashbox type), or a plastic box, sometimes inside a thick polythene bag.
Inside you'll find a visitors' book, a rubber stamp and stamp pad, and if someone has visited recently - a postcard ready for posting.
If it's the first you've ever found, you'll probably spend ages just reading the visitors' book and marvelling at the variety of ink stamps inside, and laughing at the comments. Some people have dry and wicked senses of humour! The variety of stamps come from all the individual ones carried by walkers who've stopped here and added their comments. These are very collectable: often quite beautiful, sometimes really funny, sometimes a poignant poem like Prayer for Peace.
(And you thought train-spotting, and - may the gods forgive me - megarak-ing, was crazy...?)
When you've recovered, take your own postcard, stamp it with the rubber ink stamp that 'lives' in the box, and leave it there to be collected. (No - not by Postman Pat! .... by the next walker who stumbles across the box!)
This idea isn't as daft as it sounds, as by this method you can tell how long it was, since you were there, before someone else found the letterbox!
You then add a comment to the visitors book, after spending ages admiring the stamps of everyone else who has been before you, and trying to think up something witty. Hang on tight to the pages, as they can flutter away in the stiff wind if you're not careful!
(Here I should add that once you are hooked you get your own unique stamp made, and carry that with you to stamp the books you find. Thus regular collectors can think what a jolly clever person you are for finding all these boxes!)
You take any postcards that are left by previous visitors, ready to post, and post them! Make sure everything is packed away safely and water-tight again, and replace the stones so that the box is hidden.
So - letterboxing is great fun, kids love it, and you DO get to see some lovely scenery whilst having some great exercise! If you're iffy about walking on the moor (and I guess we're not, cause we're usually stone-hunting!) it gives a purpose to the trek.
The original box was Cranmere Pool.
I believe there are sometimes 'travelling stamps' but not sure how this works.
Something is not right. This message is just to keep things from messing up down the road