Once I mentioned I wanted to do something along these lines, I got tons of responses & different ways to do it. I don't have a photo of the actual way I want to do it, although I do have an actual example my friend, Amy, let me borrow. This bottle idea is by far the fastes & cheapest. Here are the instructions on this version.
The actual version I would like to present is like a fabric envelope that you can open & the top is covered in vinyl which holds your "list" of things to look for & the bottom part is where you put the pellets or rice & all the little goodies to go searching for. I figured you could even use cut up old jeans or flannel shirts to use for the backing which would be sturdy & virtually cost free! I'll post a pic later.