I know Big Boi is asking about streaks from cleaning windows. But I wonder if the problem he's having is that the windows have some other kind of gunk/contamination. As kbshadow said, claying would be a good idea. In addition, I recently clayed my windows, and followed that with Z12 (Zaino's glass polish). YEEEEeeeeHAW! Perfect glass. Now, I can easily clean my windows with only a damp MF.