Q. I've been told that some car washes leave scratches on paint from embedded dirt in the brushes, and that the hot wax option is a waste of money. What do you recommend?
- M.K., Chicago, Illinois
A. You get what you pay for. A touchless system uses high pressure to blow dirt away, but some of it may be forced into troublesome places (e.g., salt could wind up under the trim, where it prompts rust). Washes with dancing curtains can pick up grit from previous vehicles and drag it across your pride and joy. Spinning brushes can give your paint a good sanding. One problem with hot wax is that it runs down the windows when it rains, affecting your visibility. If you're not in the mood for do-it-yourself, budget about $100 for an auto detailer (one guy cleaned every nook of our dash with a cotton swab) or visit a hand wash where two or three scrubbing technicians will supply the elbow grease.