The pressure washer makes two of the eight steps better and easier, and it is not doing the cleaning. The order below exists for one reason: keeping grit away from your clear coat, because dragging grit across paint is what puts swirl marks in it.
Before you start
Fit the white 40-degree tip and nothing narrower. Have the black soap tip ready for the foam step. Mix your pH-neutral soap with warm water in the cannon. Set out two buckets and two mitts. Safe pressure band: what PSI to wash a car.
The eight steps
1. Shade, and a cool car
Sun on a hot panel dries foam and rinse water before you can deal with them, which leaves spots and reduces dwell time to nothing.
2. Wheels first, with their own tools
Wheels carry brake dust and the coarsest grit on the car. Doing them first means that grit is gone before you touch paint, and using a separate brush means it never migrates. A wheel brush that has touched a wheel never touches paint.
3. Pre-rinse, top-down
The most valuable thing the pressure washer does. Float the loose grit off before anything physical touches the car. A foot away, white tip, working top-down so you are not rinsing dirt over already-rinsed panels.
4. Foam
Swap to the black soap tip and cover the car. Apply bottom-up, which sounds counter-intuitive and means you can see where you have been as the foam builds — the dwell works the same either way. Picks: foam cannons.
5. Dwell, two to five minutes
Long enough to loosen road film, not long enough to dry. If a panel starts drying, re-foam it. On a hot day work half the car at a time.
6. Contact wash, two buckets
This is where the dirt actually leaves. One bucket of soap solution, one of clean water. Wash a panel with the mitt, rinse the mitt in the clean bucket, reload from the soap bucket, move on. Grit stays in the rinse bucket instead of going back onto the car.
Top-down. Straight lines in the direction of airflow, not circles — a straight-line scratch is far less visible than a circular one. Second mitt for the lower panels and sills, which carry the worst of it.
7. Final rinse, top-down
White tip, a foot away, top-down. Angle across window and door seals rather than into them, and back off at badges and trim edges.
8. Dry straight away
Air-drying leaves water spots, badly so in hard water. A plush microfiber towel patted or drawn gently across the panel, or a blower if you have one. Do not rub.
The mistakes that cause swirl marks
Skipping the pre-rinse. Every bit of grit still on the paint when your mitt arrives gets dragged across it.
One bucket. The mitt reloads grit every time you dip it. Two buckets fixes this for the price of a bucket.
A sponge or a brush on paint. A flat sponge traps grit against the surface; a deep-pile mitt carries it up into the pile and away. This is the cheapest meaningful upgrade in car washing.
Circular motions. Circular scratches catch light from every angle. Straight lines do not.
Working in the sun. Dried soap is harder to remove than the dirt was.
Road salt and the underside
If you live with winter salt, the underside matters more than the paint. A wide tip at distance into the arches helps; a dedicated undercarriage tool does it properly — see the accessories list.
And before you point anything at an engine bay, read is it safe to pressure wash a car.
