Dusty car base areas

[freebeard]

What do you think makes the vertical striatioins under the spoiler and tail lights and along the bottom?

The only thinbg I can thing of is inverse Cymatics.

Cymatics
Cymatics is a subset of modal vibrational phenomena. The term was coined by the Swiss physician Hans Jenny. Typically the surface of a plate, diaphragm, or membrane is vibrated, and regions of maximum and minimum displacement are made visible in a thin coating of particles, paste, or liquid. Wikipedia

The buffeting air is vibrating instead of the car. A tiny sucking sound.

[Piotrsko]

I would guess those marks are owner generated. I get them on the golf because you have to handle the rear hatch to get it open to load.

[freebeard]

Under the taillights?