Surface Decontamination is a Vital First Step in the Paint Correction Process

A good friend of ours loses his mind every time he hears the words”paint correction” used together. As someone who prepares million-dollar exotics and rare classics for top-tier concours d’elegance around the world, he knows his stuff. The problem, he argues, is the paint is already correct, it’s just the surface that needs some refinement. After all, you’re not changing the color, just the reflection.

We’ll let you argue over what to call it. Either way, before you can work on perfecting the surface – working out the dull spots and swirls – you need the paint itself to be clean. Not just washed and dried, but clean. And that’s where surface decontamination comes in. Washing your vehicle removes the dust, dirt, pollen and other everyday detritus that’s sitting on the paint. But there’s a whole layer of material that may have bonded to the surface and won’t simply wash off. This includes tree sap, road tar, bugs and other visible material, but also microscopic particles like paint overspray, brake dust, railroad debris (most often on new cars, the result of transportation by railway) and other industrial fallout.

There are several products designed to address all these concerns, ranging from mild (clay bars) to aggressive and caustic (acids). The right one for your vehicle will depend on the type of contamination that lies on the surface and, to some extent, how long it’s been there. You’ll also want to consider your tolerance for exposure to chemicals. Clay bars – For more than 30 years, clay bars have been the preferred method of surface “decon” for most detailers. The original clay bar was created by accident, the result of a failed attempt at creating an industrial adhesive. Someone figured out that it was perfect for holding onto small particles (probably the first time they dropped it on the floor) and started considering its potential for alternative uses.

Turns out auto manufacturers (imports in particular) were looking for a safer way to remove the coating of rail dust that built up on new cars as they made their way from port of entry to a network of dealers all over the country. The prevailing method involved acid-based fallout dissolvers that put off noxious fumes as it did its job and required safety equipment and special training for the dealer staff prepping the cars.

Clay bars work kind of like a lint roller on your paint. As you swipe the clay across the paint surface, it comes in contact with and holds onto small particles, pulling them from surface permanently. A thin film of spray lubricant (soapy water or a quick detail spray work best) is applied to the paint first, providing a protective barrier between the paint and the contamination picked up by the clay, minimizing chance of the loaded clay further damaging the finish.

As the clay picks up debris from the surface, it eventually becomes darker. But the contaminated portion of the clay can simply be folded into itself to expose clean material and the job can continue. A clay bar may be usable for anywhere from a single use to multiple cleanings depending on how loaded it becomes. When you can no longer expose clean clay, you simply replace it with a new bar.

Many people don’t realize clays have a mild abrasive property to help snag fallout particles. This means different clays may have different degrees of abrasiveness. Eastwood’s Concours Detailing Clay, for instance, is available in fine or medium grade. For routine care, fine clay is usually adequate, but getting to clean paint on a long-lost barn find may require a more aggressive clay.

Clay alternatives – A more recent development is a category of products that work on the same principle as clay, but without the need to fold and knead. One such product is a clay block, which has the cleaning abilities of a clay bar but can be cleaned and reused continuously. Another alternative is a surface prep mitt. The real beauty of either of these over actual clay is that if you drop it, you simple rinse it out and continue working.

Chemicals – Chemical decontamination is usually achieved with one of two different approaches. The first is solvent-based decon products. Think of that old can of bug and tar remover that was always on your dad’s car care shelf, right next to the rubbing compound and paste wax. Solvents work to dissolve tar, oil, sap, and some paints, but are generally safe on cured automotive paints.

Another option is the old dealer stand-by: acid-based dissolvers. These still work well for eradicating metallic particles, although the side effects are the same as ever. You’ll need protective gear – rubber gloves, full eye protection, respirator, non-corrosive clothing and shoes – and you may not want to perform this service in your home driveway.

A friendlier solution is an acid-free chemical cleaner, like Eastwood Concours Almost Clay. This type of product is similar to a wheel cleaner, but designed to be used as general purpose surface cleaner for all paints, class and plastic. Spray on, watch it change color as it reacts during cleaning, and then wipe and rinse. And if you don’t? – For decades, most people didn’t bother with paint decontamination; they just washed and waxed the family truckster and put it away, satisfied that it was shinier than before. But there are good reasons to at least periodically spend some time on surface cleaning before buffing, polishing or waxing. While buffing and polishing will remove some of the same debris that clays and other cleaners will, it may not pick up particles that remain embedded in the paint and you may actually introduce new swirls and scratches to the surface.

In addition to trapping corrosive debris under your wax or sealant, these products may not get an ideal bond with the paint surface. Embedded particles can also make wax removal more difficult. In short, occasional deep surface cleaning adds very little time to your overall care routine, but the results are worth if you really care about your finish.