how do you use a clay bar?

This is probably a stupid question but, how do you use a clay bar? Ive heard a lot of people talk about them and how great they are and Ive seen them in the auto parts store but I have no clue how to use them or what they do? Thanks

These links explain in more detail: http://www.properautocare.com/usclaybartor.html

http://www.erazer.com/prod01.htm

http://carforums.com/auto_help/paint_care/car_paint_clay_bar.php

It's actually very easy and safe. The golden rule is to use LOTS of lube solution and work in the shade on a cool and clean surface. I use a wash mitt and car wash like Zaino Z7 for the lube. Then you lightly rub the clay across the lubed surface in back and forth motions until it glides effortlessly. Usually this means the job is near complete. A neat trick is to use a plastic baggy over your hand to "feel' for contamination in the paint. If it feels like sandpaper and gritty, you need to clay more, if it's buttery smooth, you're done and no need to clay. Usually takes about 1 to 2 hours depending on the condition of the paint and how picky you are. Either way, it's well worth it to include claying as part of your paint prep routine.

:)