I recently encountered a similar issue on my '07 Camry's windows, front and rear window. These spots and streaks wouldn't go away after a thorough washing. So I tried Eagle One 20/20 glass cleaner, then I used Meg's Cleaner Wax and I thoroughly worked it in, and finally I used the 20/20 twice to remove as much residue as possible. My windshield and rear window are much cleaner now compared to when I first bought the car. When I bought the car there was some sort of residue on the window the I couldn't get off, you can see it when there's a light mist on the window. Now it's all gone and my wipers suffer no ill affects from waxing my windshield.
SpinDoctor :getdown