First wash the car and get all surface grime out. Dry the car off. Then spray a small portion of the car with clay bar lube and then run the clay bar over the lubricated areas. Then go dry it off. Make sure you wax the car afterwards because clay bar takes all the industrail fall out and exhaust out of the pores of the paint. You have to seal the paint.

I recomend clay baring your car no matter how old it is. Most cars are transported by train and the rail dust embeds in the paint. If you want the technical way to check if you "need" clay bar, put your hand in a plastic bag and run it over the paint. If it is rough, then clay bar it. It will make your paint deeper.

http://www.detailyourcar.com is where I get all my supplies from. Go with the grey clay bar and the pink clay bar lube.

I like using clay bar... preferrably the meguiars.You left out that its very important to wax afterward, because wherever you picked up contaminates there is likely not any wax where the contaminates were.
Here are some pics of a freshly clay barred Envoy.
http://i159.photobucket.com/albums/t147/Eurogoldls/100_0615.jpg (http://i159.photobucket.com/albums/t147/Eurogoldls/100_0615.jpg)
http://i159.photobucket.com/albums/t147/Eurogoldls/100_0617.jpg (http://i159.photobucket.com/albums/t147/Eurogoldls/100_0617.jpg)
http://i159.photobucket.com/albums/t147/Eurogoldls/100_0622.jpg (http://i159.photobucket.com/albums/t147/Eurogoldls/100_0622.jpg)
http://i159.photobucket.com/albums/t147/Eurogoldls/100_0623.jpg (http://i159.photobucket.com/albums/t147/Eurogoldls/100_0623.jpg)

I bought a Meguire's clay bar kit a while ago but have not used it yet since I never used a clay bar before and was afraid I would mess something up. The directions say to knead the clay bar until pliable and then rub over lubricated surface (lube with Quick Detailer provided in kit).

Question.....how hard do you rub?? and should this be a circular or back and forth motion.

Pardon my ignorance. Any tips would be appreciated.

It should be a back and forth motion and you should apply steady even pressure.

I just used mothers clay bar this weekend, I was pleased with the results, it definitely made the finish smooth however it didn't remove all of the fallout in the paint as I was hoping it would.

hay guy im looking for rol barrs not show bars good rollbars do you know were i could git some?

Might want to post in a different section. You are posting in a thread that is about Clay bars are obviously about detailing, not rollover protection.