Most detailing shops are standalone businesses, sometimes connected to large carwashing operations. But a growing number of detailers are mobile operators who have trucks and trailers with mounted water tanks and do the work at customers’ homes and in office parking lots. Some shops are 100 percent mobile; others perform basic detailing jobs out-of-shop and more specialized work in-shop. Mobile operators can perform the same tasks as the non-mobile shops.

If only one technician is doing the work, a basic detailing job usually takes four to five hours to complete. It usually includes an exterior wash, claying, polishing, and waxing; an interior cleaning; and tire cleaning and treatments. Many shops also provide other services upon request, such as steam-cleaning engines, paint touch-up, and installing accessories.

Exterior Wash

Since car detailing is predominantly a thorough cleaning process, a good exterior wash is crucial. Aside from basic expectations, a detailer should get the exterior as clean as possible before proceeding with other tasks, such as polishing or waxing, since dirt trapped between the surface and the pad of a buffing machine or waxing cloth can scratch the paintwork.

Many detailing shops hand wash cars the same way you’d do it at home—with a hose, bucket of soapy water, and sponge. Some detailing shops employ a process similar to coin-operated carwashes, using a high-pressure hose that can dispense clear water and soapy water. Other shops—particularly those that are affiliated with large carwashing operations—send cars through an automated, assembly-line carwash. In general, methods that include a hand-wash component achieve better results, since the detailer can spend extra time making sure particularly dirty areas get clean.

After the car is dried, most detailing shops “clay” the surfaces to remove as many remaining contaminants as possible. Like washing, claying is a low-tech but highly effective approach in which a lump of detailing clay is pressed and rubbed over the paintwork to lift away dirt.

Paint Repairs

Any car detailer can repair minor scratches and nicks, but for more severe scratches you’ll need to have a body shop repaint areas using airbrushes and then blend in the newly painted area with the surrounding older paintwork.

For very small nicks and scratches, detailing shops apply drops of touchup paint with a toothpick or small brush. For larger nicks and scratches, shops apply touchup paint, then apply a layer of clearcoat to the area, then use ultrafine sandpaper to level out the built-up new layers, and then polish and wax the area. Touchup paint repairs won’t perfectly match the surrounding paint, but if the area is small and the worker is diligent no one will notice the repaired area.

Instead of repairing damaged areas with touchup paint, some shops will “wet sand” scratches, which smoothes out the unevenness of the finish created by the scratch. Wet sanding initially produces results similar to the touch-up method, but it removes clearcoat layers from the area. Because the clearcoat is what provides a car’s UV protection, the paintwork of a wet-sanded area will eventually look lighter than surrounding areas. Therefore, it’s usually safer to have damaged areas just touched up.

Polishing and Buffing

While the simple acts of washing, claying, and touching up nicks improve the appearance of most cars’ finishes, a car needs to be periodically polished to make the finish really shine.

How shiny a car appears is primarily a function of how much light its surface reflects. Dirt and nicks reduce shine by absorbing light; scratches in the clearcoat layers don’t absorb light, but they reflect light in different directions, which makes the finish appear dulled. Since automakers have yet to invent a scratchproof paint, cars over time accumulate minute scratches in their clearcoats from small rocks, sand, and bits of eroded roadway kicked up by other cars; from acorns and other falling debris; and from a host of other sources.

Polishing a car’s finish “finesses out” these small scratches. Shops use a rotary buffing machine fitted with a soft pad that rubs a polishing compound over the car’s paintwork. Since the polishing compound is slightly abrasive, the compound and the action of the buffing machine smooth out the uneven areas caused by scratches. After polishing, shops use a clean pad to buff away remaining polishing compound. While most shops include a light polishing in their basic detailing services, shops can improve the finish on noticeably marred vehicles with extra polishing.

The polishing and buffing steps are where the most things can go wrong. If, while polishing, a buffing machine stays too long in one spot, it will leave swirl marks; if detailers use a compound that is too aggressive, they can buff right through the clearcoat and even into the basecoat and primer. Also, a shoddy job likely will result in a noticeably uneven finish.

After polishing and buffing, wax is applied and then buffed by hand or with a buffing machine. After a final once-over, detailed cleaning of seams is performed with small brushes that dispose of wax residue. Shops should be extra careful not to get polish or wax treatments onto windows; once these substances dry, they aren’t easy to remove and create a glare when hit by sunlight.

Ask any shop you’re considering whether it uses a three-step polishing process (polishing, buffing, and waxing) or a one-step process. The all-in-one process used is inferior to the three-step process because it’s impossible to all at the same time remove scratches with a compound, buff away the compound, and apply wax.

Windows and Trim

After detailing the paintwork, shops clean the car’s windows inside and out with glass cleaner and paper towels. Shops also usually apply special treatments or polishes to convertible tops, exterior chrome, chromed plastic, and vinyl trim.

Wheels and Tires

Shops wash wheels and tires, apply dressing to the tires, and either polish or dress rims and hubcaps. If your wheels already have a clearcoat layer, they generally should not be polished since this may remove their protective layers.

Interior Cleaning

Just as carpet and upholstery in your home benefits from periodic thorough cleanings, detailing can improve your car’s air quality and prolong the life of its carpet and upholstery.

Shops start by vacuuming all interior surfaces. Some shops loosen dirt and dust trapped in nooks and crannies using compressed air.

Scuff marks on doors and other vinyl surfaces are usually treated with a brush and a specialized cleaner to soften the marks so that they can be wiped away. More difficult-to-remove spots and scuff marks can be treated with vinyl cleaners, but make sure that the detailing shop uses only water-based vinyl cleaners. Because automakers have in recent years drastically cut back the amount of plastics in cars’ interiors to reduce emissions (that new-car smell can actually be harmful), vinyl surfaces are usually much thinner and solvents that are too strong can dissolve them.

While most shops also apply a vinyl protectant to remove dust and create sheen, they should make sure they wipe away any excess protectant. If too much protectant is used and not wiped away, dust and dirt will be attracted to these surfaces; the protectant can also discolor your clothing.

To clean a car’s carpeting and cloth upholstery, most shops use specialized hot-water-extraction carpet-cleaning equipment. For heavily soiled carpet and cloth upholstery, shops may work in warm water and shampoo using a wash mitt, and then remove the shampoo and dirt using hot-water-extraction equipment. Afterward, they leave the car’s doors and windows open to allow the interior to air dry.

If you have leather upholstery, have it periodically cleaned and conditioned. Without care, leather may dry up, crack, harden, and even start to crumble off. Some manufacturers treat leather upholstery with a protective thin plastic “skin.” It’s usually easy to clean treated leather by rubbing it with a mild leather conditioner; untreated leather can be more difficult to treat and may require several “coats” of conditioner. As with vinyl treatments, shops need to be careful not to apply too much leather conditioner and to wipe away excess product. Keep in mind that, after treatment, leather upholstery may appear unnaturally shiny for a few days, since the leather needs to soak up the conditioner. But if the surface of the upholstery remains wet to the touch or too shiny or wet-looking after a few days, ask the shop to wipe everything down again.

Be aware that if your car’s leather upholstery is very dry, shops might not be able to rejuvenate it, and that, once treated, dried-out leather can take on a different shade of color.

Cleaning Engines

Some shops include engine cleaning as part of their basic detailing package, while other shops offer it as an add-on option. Some don’t offer engine cleaning at all. As with detailing the rest of your car, cleaning doesn’t make engines run better, but it can make maintenance easier, as leaks become easier to spot. Also, a dirty engine coated with grease may run hotter than a clean engine, and moving parts such as linkages work more smoothly in cleaner engines. But before having your engine cleaned for maintenance reasons, ask your mechanic if such a step is desirable.

Before cleaning an engine, the shop should cover or remove the distributor, carburetor, battery, and ignition mechanisms to protect them from cleaning solvents and water. A degreasing agent is then sprayed onto the dirtiest parts of the engine and allowed to soak in for a short time. The engine is then rinsed with a low-pressure hose that sprays water throughout the engine compartment. Some shops use steaming-hot water to rinse the engine; others rinse with tepid water and let the degreasing agent do most of the work. After washing, most shops spray down the engine compartment with a “dressing,” usually a thin water-based substance that makes everything shine. Some shops follow basic cleaning with a more detailed cleaning of nooks and crannies.

Miscellaneous Work

Shops usually clean air vents inside the car, doorjambs, steering wheel, speaker grilles, window handles, knobs, seatbelts, etc. Some shops also offer a wide variety of other services, such as installing accessories and custom work.