To answer that question watch this short video "you never want to use a spnge to wash your car. a sponge traps dirt and that dirt will scratch the clear coat on the car." <a href="http://www.youtube.com/watch?v=f0SekbX1qng&feature=related" rel="nofollow" target="_blank">http://www.youtube.com/watch?v=f0SekbX1qng&feature=related</a> @:32 seconds - "im a car enthusiast...i built and own many corvettes" The dirt gets washed right off the front of the delivery system, unlike other hand washing micro-fiber products.