Making the automotive paint surface look great is one of the most common activities of the professional detailer. It is important, then, that the technician be able to evaluate and diagnose common paint problems and offer solutions to the customer. Commonly found paint problems fall into two categories. There can be contamination on the surface, or there is damage that goes into the paint layers.


Surface paint problems include environmental fallout, ferrous oxide deposits (rail dust), paint overspray, bug and tar splatters, cement splatters, and water spots.

Environmental Fallout

“Environmental fallout” is a generic term that refers to all of the particulate crud that is floating around in the air. This stuff settles down onto the paint surface of the vehicle as it sits outside in the open air. This can be stuff like dust, jet fuel, paint droplets, industrial particulates (e.g., sanding and grinding debris), and any number of atomized chemicals released from industrial operations.

Most of this fallout by itself is not a problem for the paint, but when combined with water from precipitation or dew, the environmental fallout can become fused with the surface of the paint. In the extreme case, like acid rain, the fallout and water combination can actually etch into the paint, creating a sub-surface problem. We’ll talk about this later.

Ferrous Oxide

Ferrous oxide deposits are a specific form of environmental fallout that are made up of tiny iron particles that come from industrial operations. You may have heard the term “rail dust,” which refers to the ferrous oxide particles that come from railroads. As the train runs along the rails, the contact and friction between the steel wheels on the train cars and the iron rails causes small, almost microscopic pieces of iron to spit out and float away in the air.

Ferrous oxide particles can also come from other metalworking industries such as shipbuilding. They appear as small brown nibs on the surface of the paint. Sometimes, especially on white vehicles, there is a brown ring surrounding the particle. The total width of the ring is less than 1/32 of an inch wide. On darker vehicles, the iron particle might be surrounded by an iridescent or rainbow-like ring.

Water Spots

Water spots are left on the surface when water droplets are allowed to dry on the vehicle’s surface. The spotting is caused by leftover minerals and other solids that are contained in most tap water. As the water dries, the minerals settle onto the paint surface, leaving rings the size of the original water drops. Water spots may also occur when precipitation falls on a vehicle that is already covered in dry contamination like dust.

All of these surface contaminants cause the paint surface to feel rough, even after waxing. The remedy for minor surface contamination is to use detailing clay or the newer towels, mitts, and pads coated on one side with clay-like polymerized rubber. Heavier concentrations of surface contamination, especially ferrous oxide deposits, may require using acid washing techniques before applying the detailing clay.

Acid Wash

The acid wash removes most of the particles and the remaining particles are loosened so that detailing clay quickly removes these. Acid washing is a specialized procedure that should be performed only by trained technicians. It involves using a mild acid product designed specifically for fallout removal on automotive paint. Yes, that means using a diluted version of wheel acid or some other acid product is not advised.

Further, the acid wash procedure involves a number of important steps, including an initial wash of the vehicle using normal car wash shampoo, to remove loose dirt and grime. Next, the formal acid wash step occurs with a dedicated bucket and wash mitt to be used with the fallout. After rinsing off the acid wash residue, the vehicle is washed once more with a neutralizing solution, using a dedicated wash mitt and a stronger concentration of wash shampoo or even a mild all-purpose cleaner solution.

The acid wash can go far to assist in the loosening of heavy concentrations of fallout. Following the acid wash procedure, the standard clay procedure can be employed to remove any leftover fallout.

Those who do not wish to deal with the rigmarole of an acid wash may find an acceptable substitute by using a polymerized rubber disc with an appropriate dual-action polisher. Using just the right amount of clay lubricating spray wax on a washed and dried vehicle can yield quick and relatively easy results.

Cement Splatter

Cement splatters are difficult to remove. The best way I have found is to first spray the cement with a citrus-oil-based cleaner. The cleaner will partially penetrate the cement and help to loosen it. Use a plastic spatula or your fingernail to gently scratch off the cement. The oil in the cleaner will lubricate the paint surface, helping to reduce scratching. Unfortunately, some scratching of the paint is inevitable. So it’s necessary to polish the area after the cement has been removed.

For cement splatters, there are also chemical products that are specifically designed for removal of cement from automotive paint, and I have found that these involve a tedious, repetitive effort to completely remove the cement. Of course, if you are working on a collector vehicle, brand new car, or a dark-colored paint job, it may be worth the effort.

Removing bugs and tar can be accomplished with one of the many chemicals designed just for these contaminants. If the contamination is light, simply pour the chemical on a towel and wipe the affected area. If the contamination is heavier, it may be necessary to use a non-scratching scrub sponge to help agitate away the tar or bugs. Always apply wax to the cleaned area, as most of these chemicals will remove any existing wax.


Sub-surface paint problems occur when the damage goes below the surface of the paint. Such damage includes oxidation, scratches, chips, staining, and etching.


Oxidation is simply the drying out of the paint. Paint starts out as a liquid that is sprayed onto the car. The paint quickly dries to the point that it feels “solid.”

But the paint never stops drying out. The liquids that made up the paint before it was sprayed onto the car continue to evaporate, albeit at a slower and slower rate, over time. Without regular waxing, and after many years or heavy exposure to heat and sunlight, the paint will dry to the point that it becomes dull. This dullness or chalkiness is called oxidation.

In single stage paint systems, oxidation can be mostly removed by compounding or polishing the paint surface, which removes the “dead” paint. Assuming that the paint is thick enough to begin with, the remaining paint can sometimes be made to be almost as shiny as when it was new. It is most noticeable on single stage paint systems. On clear-coat paint systems, oxidation appears as cloudiness in the clear coat. Unfortunately, clear-coat oxidation begins deeper in the paint and is virtually impossible to remove. Waxing makes it look a bit better and helps slow the process, but there is otherwise little that can be done to correct oxidized clear coat. If the problem persists, the clear coat will eventually begin to separate from the basecoat.


Scratches are essentially small gouges into the paint. Scratches can fall into one of three categories: micro-scratches, moderate scratches, and deep scratches. Micro-scratches are super fine scratches caused by normal washing. Some people call these “cobweb” or “spider webbing.” Swirl marks, caused by inappropriate high-speed polishing, are another form of micro scratching.

Moderate scratches are those that can be removed or at least made to look less noticeable. These are often caused by incidental contact with the paint, like rubbing up against a side panel with a gym bag or sliding a box onto the trunk. Deep scratches are those that are down to the basecoat or primer. Unfortunately, these cannot be removed, nor can they be made to look less noticeable using standard detailing techniques. Some deep scratches, however, can be made to look less noticeable by using professional paint touch-up techniques.

Scratches can be filled in with glazing products, but this is only a temporary fix. The fill material will evaporate in a matter of weeks, exposing the scratch again. To completely remove scratches, the paint must be removed around the scratch down to the lowest point of the scratch. The problem is that removing too much paint can cause problems later on. So a good compromise is to sand down the scratch part way, then fill the remainder with a glazing wax.

Other Problems

Other sub-surface problems include staining and etching, which can be caused by acid rain, bird droppings, and engine fluids. Etching is when the surface contaminant eats away at the paint. Bird droppings and eggs are famous for this. It is difficult to repair etching, especially if it is deep into the paint. The best solution is prevention — educate your customers on the importance of regular waxing or sealant application.

Paint chips or nicks are caused by sharp impacts like rocks or keys or other car doors. Some nicks can be improved using remedies similar to those used for scratches. Chipped-off paint, however, cannot be improved using standard detailing techniques. Instead, professional touch-up paint techniques can be used to fill in the chip, making it less noticeable.


There are many ways that paint can become damaged. Often there are several types of damage that, combined, cause the paint to look dull and old.
Understanding the types of damage, and then using the correct chemical, equipment, and technique to correct the damage, can go a long way to making most cars look great.


Prentice St. Clair is an International Detailing Association Recognized Trainer and Certified Detailer. As the president of Detail in Progress Inc., he has been providing training and consulting to car washes and detail shops since 1999.
He is available at (619) 701-1100 or