[II kings 9:20]

Clay is a must anytime you wax otherwise you grind dirt into the finish. All that grey on your white applicator is dirt. Some have gone to grey or black applicators so you can't see all the dirt you are rubbing into the finish. I use it to remove tar, sap, stains etc. with great results. I think the jury is out on the CA duster, my brother uses one on his Diablo but all that "dust" dirt trapped in the fibers has the potential for scratches.