Koch Chemie · Germany · Exterior Pre-Wash
Highly Concentrated Alkaline Pre-Cleaner · No-Contact Formula · Road Salt Destroyer
The pre-wash that punches through road salt, wheel dust, insects, and bird droppings — without touching the paint.
Multi Star is Koch Chemie's highly concentrated alkaline pre-wash — the product the German and EU car wash industry standardized on for no-contact, high-pressure touchless cleaning. Surfactants dissolve road grime, wheel dust, insects, and bird droppings before a wash mitt or brush ever touches the vehicle. The paint never has to deal with the abrasive load of that contamination being dragged across it.
What makes it stand out from a generic APC is the built-in corrosion inhibitor package — that's why it's safe on anodized aluminum and more sensitive trim surfaces that an unformulated alkaline cleaner would attack. Think of it as a more exterior-focused, contact-less counterpart to Green Star. Same Koch Chemie alkaline philosophy, tuned for touchless pre-wash use and aggressive dilution ranges.
And road salt? Multi Star eats it. Encrusted road treatments that have baked onto wheel arches and rocker panels through a New England winter — foam it on, let it dwell, rinse without contact. It releases and pressure rinses off... and the highest selling alkaline pre-wash on the site by volume.
What it does
No-contact pre-wash — foam onto the vehicle, let the chemistry do the work, rinse with high pressure. Removes contamination before any contact wash begins.
Road salt and winter grime — alkaline chemistry breaks down encrusted road treatments and salt deposits. Rinse off without scrubbing or dragging.
Wheel cleaning — hits brake dust, road film, and wheel grime at tighter dilutions. Safe on alloy wheels including anodized aluminum thanks to the corrosion inhibitor package.
All-purpose diluted use — mix a spray bottle at the right ratio and it becomes a cost-effective general-purpose exterior cleaner. Versatility built into the concentrate.
Copolymer dewaxing — at 1:5–1:10, useful for stripping old wax or polymer protection before paint correction or coating application.
Common Dilution Guide
Do not let Multi Star dry on any surface. Alkaline chemistry interacting with a finish that's had time to dry down can cause surface issues. Manage your environment — work in shade, wet the surface first, and make sure your rinse is thorough and timely. Reaction time max 5 minutes per VDA guidelines (Verband der Automobilindustrie / German Association of the Automotive Industry).
How to Use
Dilute to task — 1:30–1:50 for standard pre-wash; 1:3–1:10 for wheels; 1:5–1:10 for dewaxing. Use a measuring tool — don't eyeball it.
Work in shade — cool, shaded surfaces only. Alkaline products and hot metal in direct sun are not a good combination.
Apply by foam cannon or spray bottle — coat the surface evenly. For pre-wash, top-down application ensures rundown coverage. For wheels, apply directly and agitate as needed.
Allow dwell time — short contact is enough. VDA Class A: max 5 minutes at 1:300 concentration. Class B: max 1 minute at 1:30. Don't push dwell beyond what's needed.
Rinse thoroughly with high pressure — full removal before product dries. Watch for the first signs of drying on the surface and rinse before that point.
Koch Chemie Official Dilutions
| Application | Dilution Ratio | Notes |
|---|---|---|
| Pre-cleaning | 1:30 to 1:50 | Depending on dirt accumulation |
| Rim cleaning | 1:3 to 1:10 | — |
| Copolymer dewaxing | 1:5 to 1:10 | Strip prior to coating or correction |
| Self-service high-pressure wash | 1:300 | Apply over whole surface; react briefly; rinse thoroughly with high pressure |