it depends really, if you have say a black car that is currently caked in a product such as SRP it will fill all the swirls pretty well. claying will remove all the product from the car not just contaminant. so once you clay if your car does look worse then before that is typically why, if you use a clay bar propper it shouldnt harm a thing. just clay, polish and wax. your car will be shiney smooth and protected.
little how to i wrote for another forum.
Claying
Claying is a technique new to most but becoming more popular. A block of what is essentially clay is used to glide over the paint work removing contaminants such as tar, bird poo, traffic film and other s**t. it works in the same way as using blue tack as an eraser.
Method
You will need - Clay, Quick Detailer, Water and a Bowl
Take your bar of choice tear or cut in half. sit in a bowl of warm water for around 5 mins (upto ten in the winter) take half the bar and work it into a patty(burger then) shape in the palm of your hand. now take your bottle of Quick Detailer(often supplied with the clay) starting with the panel you believe has least contaminants spray the panel you want to begin work on, dont be scared to spray too much on but dont go crazy it need to last a car. now spray the clay bar to make sure its a little moist. glide the clay bar across the paint work of the car in till it glides freely. fold the bar over to reveal a clean side spritz with QD repeat this all over the car, all the paint work, glass and smooth plastic such as lights can be done. OOPS you dropped your bar on the floor? luckily you still have half a bar in the bowl of water for such a case. to the touch your car will now feel smoother then a babies bottom.
Points to take note on are
-once clayed the car is fully unprotected from the elements
-if dropped the bar must be exchanged
-older clay can be used on wheels, door shuts, under side of skirts
-a light solution of shampoo and water can be used as QD if you only have a bar
