About a year ago, I ran across a filter bag that you could strain a stock through and it would clarify the stock to almost Consomme-level clarity. It seems like this was called a "magic bag" or something along those lines, but, for the life of me, I can't seem to find it again. There was a French company that was selling them specifically for cooking (at premium pricing, of course), but I also thought you could find them as simply industrial filters, too.
Anyone have any idea what I'm talking about? For that matter, has anyone here used them before?