An IBA owner that has an all-glass building told me that they rigged up sprinklers that spray RO water on the glass every night and that this prevents film build up and keeps the glass sparkling. I would think that any of the glass car wash building companies can give you some pointers. Also, it seems that a clear solar film would work great in the areas with the most buildup - when they get cloudy, just remove 'em, toss 'em, and put up some new film.