Can someone in the know please explain to me how you are supposed to use a clay bar ? I tried the meguiars clay bar kit last night and didn't seem to be getting great results. I sprayed a small portion of a body panel (2' x 2') with the lubricator provided and then rubbed the bar back and forth overlaping each pass. Then I wiped off the excess spray, buffed, then waxed. I really could tell no difference from the parts I had done to the parts I hadn't. I was expecting to see some sort of contaminents on the clay bar but could see nothing. Am I doing something wrong?