I do this. It is really the ritual or rather the physical action of writing it down on the piece of paper and putting it in the box that helps me in my mental ability to actually "turn it over."
Anyway, here are some pictures of a God Box I made. On the sides of the box are things that I turned over. There are two pictures of my ex-wife engraved on the ends of the box and picture of my boys on the front and a picture of the flatirons of Boulder, CO of which I am letting go. I am not letting go of my boys per se, rather I am letting go of any control that I might have over them. They are in the "ex's" hands. It is really "the way it was" is what I am letting go of.
I also just made a pencil box. Yea Yea Yea, I know you could care less but this is what I have fun doing. I hope to be able to make money at it some day