Hand Washing vs. Automatic Wash
Studies show that hand washing your vehicle is one of the worst things you can do to your car’s finish because rags and sponges gather grit and dirt particles that scratch the paint and clear-coat. Hosing off your vehicle often fails to remove all of the soap film, causing soap residue to melt into the finish. Soap residue eats into your car paint, therefore, it is important that all soap film is washed off of your car.
During the study, Technological University of Munich, in association with Mercedes-Benz, asked average car owners to hand wash their vehicles as clean as possible, using any supplies they choose. 25 identical new-model sedans were put to the test, and in conclusion, this study showed that automatic car washing is far superior than handwashing for protecting your car’s finish. After 25 handwashes, scientists found dense scratches on the car’s finish by using microphotography. They attributed these scratches to the dirt particles trapped in the rags and sponges that were used in the wash. In addition to the scratches, scientist also found that the typical household garden hose is unable to produce enough water and pressure to remove all the soap residues from the finish.
And now for the automatic washes! These washes were done under real-world circumstances and were performed at a modern car wash. The 25 cars were sent through the wash and micro-photos showed no sign of the scratches on the car’s finished that were created from the hand washing.