Although water works just as fine on your wiper wash, there are actually a few benefits to using specialized commercial wiper wash products today. Water, although excellent at cleaning dust on the windshields, may face substantial difficulty when removing dried splattered bugs or road tar. A specialized wiper wash that has been fortified with detergents may be able to remove those easily. Road tar, being oil based, will also be somewhat resistant to water, which does not mix well with oil. The detergent additives of the specialized wiper wash will do the trick. There are also specially scented wiper washes. This works by releasing a scent along with the wash fluid which you can smell if you open the air conditioning vents just before you activate the wiper wash.