200 gram Bar with Plastic Case

Fine grade paint detailing clay for the safe and efficient removal of bonded contaminants.


Driven on a public road or exposed to the natural environment, a vehicle’s paint is exposed to an astounding number of pollutants and contaminants. While some are harmless and easily cleansed with an autobody shampoo, others like brake dust, rail dust, and diesel particulates can aggressively bond to the paint surface, particularly when no protectant has been previously applied. Even brand new vehicles, shipped by freight train, are susceptible to such contaminants. Werkstat Prep Clay removes these micro particulates in the safest, most efficient way possible, leaving an ultra-smooth, clean finish. Subsequent polishing to remove paint defects is far safer and more effective without the risk of one of these contaminants being dragged over the paint during buffing. Waxes and sealants apply with greater ease, look better, and last longer.

Simply coat the paint surface with a gentle lubricant, like dilute AutoBody Wash, and glide the clay over the surface until clean.

Use once per year to keep your finish in top form.

Prep Clay is manufactured to our specifications in Japan. It is a fine grade clay, ideally suited for routine use without marring. We opted for a large 200 gram bar for efficiency.

Packaged in a reusable plastic storage case.


Is Prep Clay safe on all paint types, including clearcoats?

Yes. Used properly, with sufficient lubrication, Prep Clay is safe for all paint types.

Is Prep Clay abrasive?

There is a great deal of misinformation concerning the true nature of all detailing clays. First, all detailing clays contain an abrasive component. These abrasives range in cutting power from very mild to very strong. Prep Clay employs fine grade abrasives designed for annual and semi-annual use to remove routine contamination. Medium and heavy abrasive clays are most often for professional use only as they can leave significant marring comparable to that of a rubbing compound.

But I thought the “stickiness” of clay removed the contaminants, plucking them from the surface?

This is false. Actually, it is an abrasive process that removes the contaminants. The beauty of clay, however, is that the lubricant floats the abrasive clay above the paint surface. The clay therefore only exerts its abrasive force on the raised contaminants and not on the paint itself. Those contaminants are rubbed apart by the abrasives, and the “stickiness” of the clay picks up and contains the powdery contaminant residue created by this process. This is why a used, dirty clay wafer will appear to have a film of dirt over it and not larger individual particles of dirt embedded in it.

How do I know if my paint needs claying?

The easiest way to make this determination is by feel. After washing the vehicle, run your fingers over the surface. Does it feel clean and smooth? Or do you sense tiny particles on the surface? Secondarily, take a close look at the surface. Do you see any tiny rust-colored specks? These are bits of metallic dust bonded to the surface. They are another signal that it is time to clay. In particular, check horizontal surfaces, such as the roof or hood, where pollutants can easily settle onto the paint and check around wheel wells where the tires tend to spray the paint with road grime.

Why not just use a polish to restore the smooth feel to paint?

This is a common misconception. Polishes, which employ varying degrees of abrasive particles in a liquid slurry, are formulated to remove flaws within the paint and clearcoat itself, things like scratches, hazing, and swirl marks. The problem of using a polish to remove common bonded contaminants is twofold. First, unlike clay which exerts abrasive force primarily on the contaminants, a polish will exert its abrasive force equally on contaminants and the paint itself. Second, if a contaminant becomes loose during polishing, the buffing action will grind it across the paint surface, creating micromarring or scratches. It is far better and safer to use a product that matches the problem: clay for bonded contaminants on the surface and polishes for imperfections in the paint film itself.


1. Break a small 25-50 gram piece of clay from the bar and flatten it into a wafer shape. You can adjust the size until you are comfortable with it. Generally, a wafer the size of a half-dollar works well.

2. Spray the paint surface with a good quality lubricant, like Quick Wash or diluted AutoBody Wash.

3. Gently float the clay over the lubricant with light pressure. Linear back-and-forth strokes are preferable. If the clay sticks to the surface at all, apply more lubricant.

4. While moving the clay over the surface, keep a finger in contact with the paint. When the surface feels smooth and contaminant-free, move to the next area.

5. Work using only one side of the wafer. When you see that the wafer has become soiled from picking up the contaminants, fold the dirty side in on itself and flatten out the wafer again. You will now have two clean sides. Continue using the same wafer of clay until you no longer see a clean surface after folding.


Occasionally, a wafer of clay may take on a life of its own and fly out of your hand. It happens! If it hits the ground, though, throw it away. The risk of scratching the paint by an errant piece of grit is too high.

Heed the directions to use only a small wafer of clay. There are several reasons for this. First, a small wafer floats better over the lubricant. Thus, it is also less likely to stick to the paint and leave clay marks. Second, the small wafer is far easier to move over the many angles and curves of a vehicle’s coachwork, and it conforms better to these non-flat surfaces for greater cleaning efficiency. Third, if the clay wafer does hit the ground, you still have the majority of the clean bar left.

The unique cleaning action of Prep Clay is perfect for removing bonded contaminants, like break dust, from wheels. Use plenty of lubricant and be certain to routinely expose a clean surface on the clay.