Swirl marks are nothing more than micro marring in the paint surface. Under a microscope, they appear to be scratches; however, you can't feel these scratches with your fingers or finger nail.
Every time you wash or wipe down your car, you create micro marring. The severity of the micro marring depends on your tools and the contaminants present.
The reason swirl marks and other micro marring show up so prominently on black and other dark colors is because the sides of the marring reflect light. When you polish, the edges are rounded and reduce reflection.
This diagram shows what severe micro marring might look like in a cross section of paint.
Here are the ten most frequent causes of micro marring (swirl marks):
The most noticeable areas for swirl marks are the hood and trunk. On dark-colored cars, they might also show up on the doors and fenders. Bright colors do not show swirl marks as much because they reflect more light. That doesn't mean they don't get swirl marks; the marks just show up more readily on dark colors. Black, of course, is the worst of all colors for displaying swirls and other imperfections.
2. How do you remove swirl marks?
Swirl marks are removed by polishing. Use a car polish designed for swirl removal, like Sonus Sonus SFX-2 Enhanced Swirl Remover. If your swirl marks are severe, we recommend using Sonus Restore (SFX-1) first to knock them down. Follow the application of SFX-1 with Sonus SFX-2 to restore full gloss. On the modern car finish, swirl remover polish must be applied with a machine, such as the Ultimate Detailing Machine. Modern paint is too hard to polish sucessfully by hand.