[whatamidoingyo]

I enjoy this as well, but live in an area where finding bottles isn't too common. That hobby has been replaced with shark teeth hunting. I have a decent collection of them (maybe ~300).

I've also learned how to make pendants out of them.

Although, if I were you, I'd be looking for old necklaces, watches, etc. in that river. It excites me to imagine finding some old gold coins or something.