The 3 key elements to getting a car wash cleaned properly are Detergent Action, Pressure and Friction.
Touchless car washes were able to hang on to the title of the safest way to wash your vehicle for years because they could boast no physical contact with your vehicle. That’s changed and so has technology. The only friction they can create is by ramping up the water pressure and heavy blasting it which scours the paint. It also forces water to go into places it shouldn’t.
Leaving out physical contact which creates the proper friction is the same as spraying down dirty dishes with soapy water without scrubbing them down afterward. It’s just not enough to remove the baked-on dirt, grime and mag chloride that cars pick up on the road. So, since they can’t create the proper friction they compensate by using harsh, concentrated cleaning products that will eat a vehicles clear coat.