The other day, I mentioned using an old credit card for removing algae from glass. (Being a well-liked teacher who doesn't drink much coffee, I always seem to have several unused starbucks gift cards floating around; they work great, too)
Anyway. Someone in another forum mentioned Mr. Clean Magic Eraser Pads, the ones with no chemicals, so I finally got some and tried them out tonight. Oh my word. These things just flat erase algae. They even erase it from the scratches in the glass. They remove it from the corners without harming the silicone. I think I'll keep a starbucks card around for removing black brush algae, because nothing else really works on a bad BBA infestation.
But for the normal black/green glass crud? Mr. Clean Erasers all the way, baby!