If a finish is properly perpared, it is polished using abrasives. These chemicals can finish to a "swirl free", mirror finish. After which wax (natural) or sealant (synthetic) is applied. Sometimes, to save on labor, a glaze is used. A glaze fills in imperfections, and covers them like make up. It is then coated with a wax or sealant.
The problem is a glazed car can be revealed with one wash cycle.
The other problem is that some operators aren't using enough
soap and water on their cloth. At my last job, we had someone from Chrysler Tech Center bring one of their brand new mini vans through our wash 100 times, testing a new wheel paint process. We ran a normal operation that day, washing some extremely dirty, muddy cars and trucks. At the end of his visit we inspected his factory fresh vehicle, and yes there were some visible hairline scratches that could only have been instilled by our brushes. We installed a set of 18" bristle brushes and they're leaving deposits on all our cars, and the bosses car. I'm using cloth on my Peco 118's, and my guys aren't having that problem. I do use more
soap and water on my brushes though...