BG is BG Specialty Co. They make the cleaners for transmission flushers, anti-freeze flushers, carbon cleaners and all kinds of aerosol cleaners and lubricants. You'll probably have to go to a shop or dealership to find this brand but a lot of places carry it.
I'm not sure what's in the Brake Quiet, but you saturate the lining with it and wait until it evaporates dry, then reinstall your drums and you're done. It was developed to help eliminate noise in the high metallic pads, but does work well on shoes too.
Scott
