Koch Chemie Vorreiniger B | Pre-cleaner and insect remover (1 L)

A pre-wash that removes dirt before you even touch the mitt

If you're wondering how to wash your car without scratching the paint, it always starts with one step – a quality pre-wash. Koch Chemie Vorreiniger B is a powerful pre-wash product that removes most impurities before you ever touch the car with a mitt.

And that is exactly the point. The more dirt you remove without contact, the lower the chance of scratches in the paint.

This alkaline cleaner with a pH of 13 works as both active foam and an insect remover in one step. It dissolves grease, road film, insect residues, and other road grime that would otherwise stick to the paint.

It is used in detailing studios as well as by people who want to keep their car washing under control and do it properly.

What to realistically expect from Vorreiniger B

• Significantly makes washing the car easier – removes most dirt without contact.
• Powerful effect on insects, grease, and road grime.
• Works as active foam and a pre-wash in one.
• Helps prevent scratches during hand washing.
• Suitable for the bodywork, wheels, and other parts of the car.
• Thanks to its concentration, it lasts for a really long time.

Recommended dilution

• Bodywork pre-wash (solution): 1:30 – 1:50
• Wheel cleaning: 1:3 – 1:10
• Foamer (touchless wash): 1:1 – 1:2

How to use Vorreiniger B to make it effective

Usage is simple, but it has its rules:

1. Apply to a dry car (ideally in the shade and on cool paint).
2. Apply using a manual foamer or a pressure washer foam lance.
3. Let it work briefly (approx. up to 1 minute).
4. Do not let it dry – this is crucial.
5. Rinse thoroughly with a water pressure.
6. Proceed with hand washing (shampoo + mitt).

Why this product makes sense

Because washing a car isn't just about shampoo. If you skip the pre-wash, you drag dirt across the paint and create micro-scratches.

With Vorreiniger B:

• you remove maximum dirt without contact
• you speed up the entire washing process
• and most importantly, you protect the paint

What to watch out for

• Do not use on hot paint or in direct sunlight.
• Never let it dry on the surface.
• Follow the dilution ratio – it is a concentrate.
• Before first use, test on a less visible area.

Koch Chemie Vorreiniger B is exactly the type of product that makes the difference between "washed" and properly washed. If you want scratch-free paint and to keep the washing process under control, you simply cannot skip this step. For cleaning wheels, you might also find a suitable wheel cleaner useful, and for finishing the wash, the Koch Autoshampoo.

Frequently asked questions

What dilution should I use for a bodywork pre-wash?
For the bodywork, we recommend a dilution of 1:30 to 1:50, for wheels 1:3 to 1:10, and via a foamer for a touchless wash 1:1 to 1:2.

Why must the product not dry on the paint?
A dried alkaline solution can leave marks on the surface or damage sensitive parts – therefore, always rinse it off thoroughly within a minute.

Can it also be used on wheels?
Yes, at a stronger dilution of 1:3 to 1:10, it also works as an effective wheel cleaner.

Do I still have to wash the car with shampoo after using Vorreiniger B?
Yes, Vorreiniger B serves as a pre-wash – after rinsing, proceed with a regular hand wash using shampoo and a mitt, for example, Koch Autoshampoo.