Updated: Aug 30, 2019
The problem was all of the other cars and the stuff, or “media,” that clung to them from driving around all day. If the car before yours went on a dirt road, for instance, it would pull into the carwash just covered in mud, sand, small bits of rock including granite, which is extremely hard and abrasive.
That grit tends to stick onto the cleaning apparatus/brushes of the carwash, which after a while can start to almost be like sandpaper. “Some of those car washes, seriously, I’ve seen them where the brushes are gray to brown with dirt.” Richard
With the high speed of the cleaning machines and the high pressure of the water, all that dirt and grit is rubbed along the surface of your car on its way off the body. And with it, can come a little bit of your paint.
Eventually, your car could end up with what’s called a “spiderweb scratch,” which basically looks how it sounds.
So how do you know how good the protection is on your car?
Here’s a Before & After video from Mindful Detailing. You can watch if you really want to see how it’s done:
San Diego's 5-Star Automotive Aesthetics Specialist