A concentrated solution of lye or sodium hydroxide (about 10%) will do the trick. No need to mess with sulfuric or dichromate. It may take a bit of soaking. But unless there is something special about the glass I would toss it and start fresh - a more effiient use of your time and money.
I use standard tray cleaning dichromate/acid solution that I make up from an old formula. If you are doing a one-time quick cleaning, then lye is acceptable, but don't leave it in the solution overly long.
Some glasses are not subject to this, for example the good labware glass we use is immune to this for the most part (pyrex), but window glass is very prone to the problem. I use a glass bottle for my 5% sodium hydroxide solution and the glass is quite milky on this cheaper glass dropper.
As for images remaining behind, I never heard of it, but I guess it is possible if sliver metal gets depositied on the glass somehow. Maybe that is why old-timers use the acid dichromate method, as it removes silver deposits that the alkali will not deal with.
If you need ground glass for your camera though, Dave Parker from Satinsnow will custom make you one for a very reasonable price.
PE