Most swirls in the paint form not during washing, but during drying. Rub a towel across the paint and you drag fine dirt particles that leave tiny scratches. So you dry safely by blotting or dragging with a thick, plush microfiber drying towel, from top to bottom and in straight lines. A drying aid or quick detailer reduces friction even further and leaves a thin layer of protection at the same time.
Why drying causes scratches
After washing there is always some fine dust and dirt left on the paint, even if you washed carefully. Move a towel across the surface with pressure and those particles rub along and pull the rings you see back as swirls in the sun. The less friction and the cleaner your towel, the smaller the risk. A thick plush towel absorbs the water through capillary action, so you do not have to scrub.
How to use it
Let most of the water run off first. Rinse with an open hose without a nozzle, so the water sheets off the panels in a smooth film instead of a thousand droplets. Far less water is then left to dry.
Work from top to bottom: the roof and windows first, then the hood and trunk, then the sides, and the lower panels and bumpers last. They are closest to the ground and the dirtiest.
Blot or drag, do not rub. To blot, lay the drying towel flat on a wet panel, press gently without sliding and lift it straight off. To drag, pull the towel slowly in straight lines following the shape of the car, without pressure, and let the fibers absorb the water.
Rotate the towel to a dry side often and replace it once it is saturated. For even less friction and instant protection, mist a drying aid or quick detailer onto the wet panel before you dry.
A blower for the crevices
Water often keeps running out of mirrors, grilles, badge edges and window rubbers after drying and later shows up as streaks on the paint. An air blower pushes that water out of the crevices without touching the paint. Especially on a car with a ceramic coating, where water beads off quickly, a blower is a welcome addition because you barely have to touch the paint anymore.
Why a good drying towel
A thin or cheap towel absorbs little water and forces you to rub and go over the same spot several times, exactly what you want to avoid. A thick plush drying towel with a high GSM holds a lot of water and has soft, seamless edges that do not scratch along panel edges and glass. That way you dry a panel in one or two passes instead of scrubbing.
Common mistakes
Rubbing in circles or scrubbing with pressure. That is exactly how swirls form; work in straight lines and let the towel do the work.
Using a towel that has been on the ground. It is full of grit; never lay your drying towel on the ground.
Working from bottom to top, spreading dirt from the lower panels upward.
Letting the car air-dry in the sun. The water evaporates and the minerals stay behind as water spots.
If you do let the car air-dry, you will almost certainly get water spots. Read how to tackle those in the guide on removing water spots and limescale.