Glossary
Swirl marks
Fine circular scratches in clear coat, usually caused by poor washing and drying technique, most visible in direct sunlight.
Swirl marks are fine, circular scratches sitting in the top layer of clear coat, typically arranged in overlapping arcs from whatever motion caused them. They are usually invisible under normal indoor lighting and only become obvious under direct sun, a flashlight held at a low angle, or bright dealership style lighting, which is why many owners do not notice them until they look closely.
They are almost always caused by dragging abrasive particles across the paint during washing or drying, whether that is dirt trapped in a mitt, a single shared wash bucket, a dirty towel, or automatic car washes with brushes that touch multiple cars. Because clear coat is thin, even light grit repeated over many washes gradually etches these marks in.
Preventing them matters more than removing them, since correction always means removing a layer of clear coat. Safe washing habits, the two-bucket method, quality microfiber towels, and claying before any friction based step all reduce the grit that causes swirls in the first place. A common mistake is using dish soap or all purpose cleaners for washing, which strip protection and leave paint more exposed to marring on the very next wash.