The results are depressing, at least to the car owner who, up to now, has firmly believed in hand washing. The deepest scratches after hand washing had a depth of more than one-tenth of the paint surface. Under the microscope, the paintwork looked like a cratered landscape. The paintwork was deeply scored and scratched – the result of dirt and trapped sand particles. In handwashing, invariably too little water is used. Even with a garden hose and a sponge technique, small sand particles lodge themselves firmly in the fine pores of the sponge or wash mitt and cannot be removed even by good...

It’s a fact, hand-washing at home can leave scratches in your car’s paint as deep as 1/10 of the paint’s total thickness that reduces your vehicle’s shine. The International Carwash Association working through a special Carwash Research Foundation Grant to the University of Texas at Arlington, Texas, has conducted extensive car washing tests to determine the effect on car finishes by comparing various car washing techniques ranging from professional car washing to the bucket and sponge used by many auto owners.Research study shows that hand washing of cars at home is...