What is self cleaning?

Ceramic and graphene coatings are sometimes described as "self cleaning", and to some degree they are.

Because the paintwork is so shiny, there is very little for dirt and dust to cling to, and so when water hits the car, the dirt would rather stick to the water. But because the coating is also very hydrophobic, the water is repelled, rolling off the paintwork, taking the dirt with it.

Just recently, we had two customers come back to us for other work, who had their cars ceramic coated almost a year previous. As one of the major benefits of ceramic coatings is how easy they are to wash, we asked them how easy it had been to clean their cars. Both said that they hadn't actually cleaned their cars since having the coating, as they just weren't dirty enough to warrant it.

Of course, rain won't wash away all the dirt, so we would recommend giving your car a wash once in a while. "Self cleaning" is not really a feature which was designed into ceramic coatings, as much as a fortunate side effect.

What this question is really about

When people ask what “self-cleaning” means, they are usually trying to work out whether a coated car will clean itself, or at least stay clean without regular washing. The term sounds literal, but in car care it describes a behaviour, not an automatic process.

What self-cleaning actually means on a car

A self-cleaning surface is one where dirt struggles to stick strongly. Ceramic coatings create a smoother, chemically resistant surface that reduces how firmly contamination bonds to the paint.

• Dirt and grime adhere less aggressively
• Water movement helps carry loose contamination away
• Cleaning requires less effort and less agitation

Why rain alone doesn’t clean the car

Rain can remove loose dust, but it does not replace washing.

• Rainwater contains minerals that can leave deposits
• Traffic film and oily grime still remain
• Water dries unevenly, leaving marks behind

Where the self-cleaning effect is most noticeable

• During gentle rinsing before a wash
• When drying the car after washing
• On vertical panels where water sheets off easily
• In reduced need for scrubbing during cleaning

What self-cleaning does not mean

• The car does not clean itself without intervention
• It does not prevent dirt from landing on the car
• It does not eliminate the need for washing

Why the term is often misunderstood

• It is borrowed from architectural glass and coatings
• Marketing language implies automation rather than reduced effort
• Water behaviour is mistaken for cleanliness

How to get the most from the self-cleaning effect

• Rinse loose dirt away before touching the paint
• Wash using safe techniques and suitable shampoos
• Remove bonded contamination when it builds up
• Keep the coating free from mineral and traffic film masking

Best-practice takeaway

• Self-cleaning means dirt releases more easily
• It reduces effort, not responsibility
• Washing is still required, just safer and quicker
• A clean coating performs better than a contaminated one

Written by Danny Argent. Last updated 23/01/2026 15:13