I have a black f150 Harley and bought Zaino, with 100% cotton towels after reading numerous posts on an f150 forum. They swore by the towels, but made sure to stress that the cotton towels are USA made, not pakistan like you get a Kmart, Walmart or the auto stores. They specifically mentioned Cannon towels, so I bought those. My truck has developed swirl marks over the last year, and I couldn't figure out why. I have tried 3 different wash mits thinking it was those.
I just bought a brand new Lexus RX330 (black) and started the zaino process. I started with a clay bar, then drying the residue with the 100% cotton towels. I immediately noticed small minute swirls scratches. I stopped immediately and came inside and ordered 75.00 worth of Microfiber towels. I will never use the cotton again. I have two other MF towels, so I know they are softer.
RickC