I had questions on the clay bar, here are answers I got from the
Detail Forumhere:
Slide your hand in a plasic sandwich baggie, then rub your hand lightly over the surface. You will feel so much more this way than just with a bare hand. Once you feel your finish becoming rough then it's time to clay.
If you are not familiar with the clay bar, go to the Adam's Website
http://adamspolishes.com/ and on the right side of the page, there are free instructional videos including a video on "Clay Bar". The quick version: A clay bar is just that, a hunk of clay that you rub over your paint that will remove all the impurities from your paint. One bar, with normal use is good for about 8-10 uses.
Regardless of how clean you think your paint is, there is still contamination stuck on the paint that you need to remove before waxing or polishing your paint. Clay bars leave behind an ultra-smooth surface that will make your wax adhere better and last longer. It also makes the wax much easier to remove, reducing your "elbow grase" substantially. Clay is safe for all paint and also works great on glass to get it sqeaky clean. Clay bars are best used with a lubrant such as Adam's Detail Spray or soapy water. Follow up with a good polish or if you are satisfied with the finish after clay bar, use your favorite wax.
Over 70% of all new vehicles are shipped from the factory via rail, therefore infecting the vehicle before it even gets to the dealership.
Anytime a vehicle is parked or travels near a railroad it is subjected to rail dust contamination
Brake dust is produced from the friction of the brake pads rubbing against the rotor.
Since all brake pads are no longer made of asbestos, and are made of metal particles, during braking, metal on metal friction disburses tiny particles of bare metal onto the paint finish of all automobiles.
Industrial fallout is another term used to describe pollution, this contamination is settling onto the paint finish of all automobiles and causing equal damage as rail dust and brake dust when left untreated
1. Clay isn't just for paint. You can use detailing clay on any smooth, hard surface, including glass and chrome. Do not use clay on clear plastic, such as headlight lenses.
2. Clay is not a cure-all or a replacement for polishing. It's a tool for quickly and easily removing surface contamination. One of the many reasons for using clay is the removal of brake dust. Brake dust contamination, which attaches to painted rear bumpers and adjoining surfaces, is a metallic surface contaminant that can be removed safely and effectively by using clay. When contaminants get a solid grip on your car's paint, washing alone may not be enough to remove them. Pre-wax cleaners also may not be able to exfoliate large particles. In this case, you have two choices: use a polishing compound, which removes a lot of paint material, or use a clay bar. Clay isn't a polish or a compound, it is a surface preparation bar that smoothes the paint and exfoliates contaminants.
Using a polish after a clay treatment will remove swirls out of the paint finish that will make your paint optically improved as clay bar will not remove swirls.