I use microfiber and the two bucket system with grit guard. If car is filthy I rub the mit on the guards even more to knock off any dirt/debris that could be stuck to the mit. No scratches! A sponge, wool mit, etc are going to be coming into contact with the same dirt/debris and will be stuck on the mit just as it would be on the microfiber. Microfiber you can see what is on the mit itself as you can a sponge. The wool mits or any mit with the long hair/fabric can hide the dirt/debris causing you to swirl/scratch the paint as you cant easily see it on the mit all the time. My
