I'd like to submit my Ogham "coins" to the competition. Following a walk in the woods, I was gifted a branch of Silver Birch (it had fallen from the tree, so I said a collected thanks). after leaving the branch to settle, I then whittled the bark off, sanded the section down to remove any rough edges, then cut 15 disks, all roughly equal size.
I then sanded the corners off each disk and smoothed the surface, before burning the symbols onto one side using a flat soldering iron. I haven't varnished or sealed them in anyway so that my contact will further link them to me.
I keep the disks in a (bought) velvet pouch - and randomly pick a disk as a "guide for the day".