Good to see you all using my thread as a reference...I am proud that I put that up a while ago. I knew it was going to be usefull and it makes me happy to give people a new meaning to what it takes to maintain their cars properly. I will always suggest polishing your paint after clay barring. Being that clay bars are mildly abrasive, they might create light marring of the surface that is easily removed by machine and a light polish. I've never liked the hand in a sandwich bag thing. I never felt anything but the surface of the plastic when I tried this. A naked, clean hand works fine at telling if a surface needs to be clay barred or not.