An automatic wash is good value for what it is built to do: get road salt, sand and bird droppings off before they have time to cause damage. If you drive past one and decide that will do for today, you are usually right.
The problem starts when that same wash is all the car gets for five years. The consequences build up quietly, because they are invisible in the rain you drove in through — and visible only in sunlight, afterwards.
Here are seven of them, with what you can do about each.
The seven points
The brushes carry the last car’s grit
The brushes themselves are soft enough. What scratches is what they carry: the car ahead of you brought in road sand, brake dust and small stone particles, and some of it is still in the brush when it reaches your bonnet.
The result is swirl marks — thousands of micro-scratches in the clear coat, all roughly the same depth, all in the same circular pattern. Too fine to feel, too shallow to see on an overcast day. In direct sunlight, viewed from the side, they look like a spider’s web that follows you as you move.
They sit in the clear coat, which is a few hundredths of a millimetre thick. No wash removes them, because they are not dirt — they are missing material. Only machine polishing takes them out, by levelling the clear coat down to the bottom of the scratch.
Check it yourself: park in sunlight and look along the bonnet from the side.
The water has been used before
Most wash halls recycle their water. That is both required handling of oily waste water and sound practice, and there is nothing wrong with it in itself.
But recycled water is filtered, not clean. The filters catch the large particles; the finest ones go round again. That is why a well-run hall finishes with a clean, often desalinated rinse — and that final step is what separates a good hall from a cheap one to operate.
The same applies in a self-service bay: the sponge hanging on the wall has been on forty cars since it was last rinsed, and it has been on the gritty floor at least once.
Bring your own microfibre mitt to a self-service bay. It costs very little and lasts for years.
Degreaser must never dry on the paint — but it gets the chance
Degreaser is alkaline. It works by sitting on the surface for a few minutes and then being rinsed off while still wet. That is the whole instruction, and it is printed on the container.
In a busy hall on a warm day it dries on the bonnet before the nozzles come back. The chemistry stays on the surface instead of being washed away, and that is what leaves streaks and dull patches.
The unpainted parts suffer most: black plastic trim fades, bare aluminium on wheels goes dull, rubber seals dry out. The wash is not the problem — the time between application and rinsing is.
Never wash in direct sun. Warm paint dries the chemistry in before you can rinse it.
Machine «wax» is rarely wax
What gets sprayed on in the final stage is usually a polymer or silicone emulsion. It lands on wet paint, makes water sheet off instead of beading, and gives a shine that looks convincing as you drive out.
Its main job is to get the car dry without drying marks. Protection is a side effect, measured in days rather than months — after two or three washes it is gone.
Real wax or a synthetic sealant goes onto dry, clean paint, is given time to bond, and lasts for months. Ceramic coating is the same idea, harder, measured in years. Neither can be sprayed onto a wet car in nine seconds.
If water still beads two weeks after a wash, you have protection. If not, you had a drying aid.
The interior gets vacuumed, not cleaned
A machine does nothing inside. What is called an interior wash in a service hall is usually a quick vacuum and a cloth with all-purpose cleaner over the dashboard.
That cleaner often leaves a shiny silicone film. It looks clean for two days, attracts dust, and reflects into the windscreen when the sun is low.
What is not done: the seats, where dirt sits down in the fibres rather than on top of them; the air vents; the seat rails; the belts; and the gap between seat and centre console, where everything ever dropped in the car has ended up.
Press a palm into the seat. If it feels stiff or tacky, the dirt is in the fibres and a cloth will not reach it.
Headlights turn yellow, and no wash stops it
Headlights are polycarbonate with a thin UV-protective coating on the outside. Sun, road salt, sand and detergents wear that coating away — including the detergents in the hall, which are stronger than what you use at home.
Once it is gone, the plastic underneath oxidises. The yellow is not stuck-on dirt; it is the material itself breaking down. Washing more often does not make it lighter.
It is not only cosmetic. Hazy plastic scatters light instead of letting it through, so the beam loses both reach and its sharp cut-off — most noticeable on unlit roads, which is exactly where headlights earn their keep.
The fix is to sand off the oxidised layer through several grits and re-seal the plastic with UV lacquer. Polished without a new seal, the yellow is back within a year.
We charge kr 1 000 for two lenses and kr 1 500 for four — with a new UV seal, not just a polish.
What you can genuinely do yourself — and when it pays to hand it over
Most of this you can do yourself, and some of it you should. A car washed properly every other week rarely needs more.
The rule is simple: maintenance you do, correction you hand over. They are not two levels of the same job.
Washing without adding new scratches
- Two buckets: one with shampoo, one with clean rinse water. Rinse the mitt in the clean one before it goes back into the soap. This single habit prevents more scratches than anything else.
- Rinse loose sand off at low pressure before anything touches the paint.
- Wheels first, with their own bucket and brush. Brake dust is metal.
- Use a pH-neutral car shampoo, not washing-up liquid — that strips whatever protection you have.
- Work top down, in straight passes, never in circles. Circles are the pattern you are trying to avoid.
- Dry with a large, soft microfibre towel laid on and drawn across — or let it absorb, without rubbing.
- Never in direct sun, never on hot paint.
When it pays to hand it over
Four cases, and they have one thing in common: they are not maintenance. They are correction — restoring something that has already got worse — and they need a machine, experience and a paint depth gauge.
- Swirl marks and dull paint. Polishing levels the clear coat to the bottom of the scratches, and done wrong it cannot be undone. One-stage polishing is kr 2 399 with us for a small car.
- Lasting protection. Ceramic coating is kr 8 999 including three-stage polishing as preparation — and the preparation is the job, because a coating over uncorrected paint locks the flaws in under a layer meant to last for years.
- Seats and interior, once the dirt is in the fibres rather than on the surface.
- Selling. A car being sold earns a full preparation back several times over, and it is the one occasion a buyer deliberately studies the paint in sunlight.
For the record
A well-run modern hall with soft textile brushes and a clean final rinse is better for your paint than a poor hand wash with the wrong sponge. It is not machine versus human — it is what sits in whatever touches the paint, and how long the chemistry is left on.
Prices are ours, based on a small car. SUV adds 30 per cent, van 40.
We come to where the car is
Ren Mester is mobile car care in Tønsberg and Vestfold. We come to your home or your workplace, with our own water and power, and you get a fixed price in writing before we start — not an hourly rate, and no invoice afterwards you did not expect.
If you are not sure what your car needs, say so. If it just needs a wash, we will tell you.
See prices and available times