Where can you sell crushed glass?

It really depends on where you live, if you are lucky their might be a mill near you who will buy it by the pound.

If you arent that lucky, you could put up flyers or try Craigslist looking for Glass-Blowers, they are always ontop of stuff like they because they can melt it into a liquid then blow it into some beautiful art.

If you cant find any glass blowers maybe you could look into blowing glass yourself ?, If you have enough crushed glass you could make a lot of money doing so.

Hope i could help even putting an idea in your mind [: