Car Wash: How a Clay Bar Actually Cleans Your Paint

We may yet get into more tips about how to wash a car, but was shown this page yesterday and thought it had some good information about how detailing clay works (even if it is written by a person trying to get you to buy their brand of clay):

1. Detailing clay works by hydroplaning (floating) over the surface you’re cleaning on a thin layer of clay lubricant.
2. When the clay (polish) encounters surface contamination, it abrasively grinds it away.
3. Detailing clay shears off any foreign material above the level surface of the paint.

Learning to use a “clay bar” properly is a handy skill to have when trying to put a car’s paint job back in pristine condition. Because it is an abrasive, though, it isn’t a good idea to do it constantly, unless you have one of the special light abrasive varieties that don’t actually do much all that much.

For most people, claying out a car is unnecessary, because you just don’t care that much about you car’s paint job. Start with a good wash and a wax. You’ll probably be surprised how much of a difference that can make.

The Making of a New Detailing Clay [GuideToDetailing.com]