Try this: ArmorAll Glass Wipes

I have a hard time cleaning my car windows, and after a trip with the dog, the windows are covered with slobber and nose prints. Windex and paper towels always leaves streaks for me. This time I tried these ArmorAll Glass Wipes, and they lived up to their promise of a "Crystal Clear, Streak-Free Shine." Try them! They were available in my grocery store for about $5.