Heard / read somewhere (sorry, can't recall the source) that the kind of glass you can put to be recycled is only jars and bottles, not broken drinking glasses and stuff; the latter can't be re-melted the same way. I suppose it's that "crystal" glass is done at a much higher temperature, so mixing that in means it can't be re-used for jars and bottles. Should have hot the hint from how much thinner than simple containers tableware glass can be, and how much sharper the shards are. I only put jars in there now and save the rest for when I go to the recycling centre, where they have a more fine-grained classification of bins to put stuff in. But of course the glass bin in our building still has table glasses and vases and stuff in it, because most people don't know this.