I have a customer that purchased a fleet of used work vans from a rental agency. They were originally orange or yellow and were repainted after the customer purchased them. However, painting the door-jambs were an extra $150 per door, so in an effort to save money they declined. The customer just wants to make the door-jambs white, and he was thinking of painting them with white spray-paint. It doesn't have to be perfect, just has to be white. How should I go about scuffing up the original paint? What process should I go through? Any suggestions?