Pre-wash
A pre-wash is the stage before the contact wash, where chemicals or foam loosen and lift dirt so less of it is dragged across the paint by hand.
What it means
A pre-wash is everything done to a dirty car before a mitt touches it. The goal is to remove as much grit and grime chemically as possible, because every particle lifted off without contact is a particle that cannot be rubbed across the paint and turned into a scratch. A typical pre-wash has two parts. First, a pressure rinse knocks off loose dust, sand, and mud. Then a clinging product is applied and left to dwell: snow foam from a foam cannon for general road film, or a dedicated pre-wash spray for heavier traffic film and bug residue. The chemistry breaks the bond between the dirt and the paint while the foam or spray holds it in place. A second pressure rinse then carries most of the loosened dirt down and off the car. Only after that does the contact wash begin, and by then the surface is far cleaner than it looked at the start. A proper pre-wash is the single biggest thing a wash routine can do to avoid swirl marks.
Why it matters in Singapore
Cars in Singapore sit through sudden heavy rain, then dry in strong sun, which bakes road film and tropical sap onto the paint. A thorough pre-wash dissolves that baked-on layer before any cloth is used, which protects the finish and matters even more for the dark, glossy paint and coated cars that are common here and show every swirl.
How Revol Carz handles this
Revol Carz treats the pre-wash as a fixed stage of its detailed grooming and wash work. The car is rinsed, foamed, left to dwell, and rinsed again, so the contact wash that follows starts on a surface where most of the grit is already gone.