Chemically bind stubborn dirt: When water and microfiber cloths are no longer enough

When people first hold an alkaline intensive cleaner and read "pH 12.5" on the label, they often think, "This is for professionals." However, Koch-Chemie Mzr is the exact opposite. It's a concentrate that, when diluted 1:20, becomes an everyday helper for interiors, engine compartments, and soiled seat upholstery. The crucial difference lies in how it attacks dirt: not mechanically by rubbing, but chemically through alkaline hydrolysis. This makes it indispensable for tasks where normal cleaners don't cut it.

Koch-Chemie Mzr dissolves oil, grease, nicotine, and graying through chemical reaction rather than friction. If you know the dilution ratio and avoid forbidden surfaces, you have a cleaner for almost all tough tasks in your vehicle.

What distinguishes Koch-Chemie Mzr from an ordinary all-purpose cleaner

Koch-Chemie Mzr is an alkaline intensive cleaner with a pH of 12.5. This value is not a marketing promise, but measurable chemistry: Alkalis dissolve fats and oils through hydrolysis. Dirt particles are chemically bound before you even have to work mechanically. This is the structural difference compared to conventional household all-purpose cleaners, which usually have a pH between 7 and 10.

In cars, layers build up that cannot be completely removed with pH-neutral products: skin oils on the steering wheel and gear knob, nicotine films on the headliner, burned-in dust particles in fabric seats, oil vapors in the engine compartment. Against these organic substances, pH 12.5 works at a molecular level. It breaks down fat chains, so the microfiber cloth only needs to wipe them away afterward.

The Daimler approval that Mzr carries is a concrete sign of quality: For workshop use on Mercedes-Benz Group vehicles, a cleaner must pass defined material compatibility tests. The fact that a concentrate with pH 12.5 receives this approval shows that it can be used in sensitive vehicle environments when correctly diluted.

A concentrate with a pH of 12.5 must also be formulated so that, when diluted, it does not attack surfaces it is not intended to attack. Koch-Chemie explicitly states textiles, plastics, and industrial surfaces as areas of application. This is also reflected in its composition: The formulation is designed for biological and organic contamination, not mineral. Limestone and rust are therefore not well addressed – for these tasks, acidic cleaners are needed.

If you're wondering whether Mzr belongs in the all-purpose cleaner category or more in the interior cleaner category, here's a clear answer: Mzr covers both fields, with the caveat that you know its limitations. The distinction from other products in Koch-Chemie's cleaner range will follow in the later section on comparison and application logic.

Mixing ratio and dwell time: How to use Mzr correctly

Mzr is diluted with water depending on the degree of soiling. The ratio determines how strong the solution will ultimately be. For normal interior contamination, 1:20 is a good starting point: one part Mzr to twenty parts water. This results in a working solution that works reliably on seat upholstery, carpets, and plastic surfaces. For more ingrained stains or heavily grayed textiles, 1:10 or even 1:5 may be appropriate.

The practical procedure: Fill the mixture into a spray bottle, spray the surface evenly, and let it dwell for 30 to 60 seconds. During this time, the pH 12.5 begins to break the bonds between dirt particles and the surface. Afterward, mechanically work it in with a brush or a microfiber cloth. The cleaner has already loosened the bond. The mechanics only lift it off. Finally, remove residues with a damp cloth or, for seats, use a wet-dry vacuum cleaner.

For fabric seats and carpets, a brush is a more suitable tool than a flat cloth. Bristles penetrate the fabric structure without tearing fibers. The Koch-Chemie Interior Brush is specifically designed for this application: soft bristles that work even in finely woven upholstery without leaving marks. The difference from a hard household brush is particularly visible on light-colored seat covers or beige textiles.

Two points of application are non-negotiable: First, never work on hot surfaces. If the car has been in the sun, open the doors and wait until the surfaces have cooled down. Second, the solution must not dry on the surface. This concentrates it uncontrollably and can leave residues that are difficult to remove. In the engine compartment, always work with the engine off and cooled surfaces.

The mixed solution in the spray bottle has a shelf life of four weeks. After that, it loses effectiveness. If you use Mzr seasonally, you should empty the spray bottle after spring use and mix a fresh batch for the next use. The concentrate itself remains stable for 24 months, according to the manufacturer, when stored at 5 to 30 degrees Celsius.

One liter of concentrate yields 21 liters of working solution

When someone buys Mzr for the first time, they often only consider the liter price of the concentrate. The real cost-effectiveness lies in its yield. At a 1:20 dilution, one liter of concentrate produces 21 liters of ready-to-use working solution. This covers a complete spring cleaning of the vehicle, including the interior, door jambs, engine compartment, and trunk. The one-liter container remains usable.

This is the strength of concentrates compared to ready-to-use spray bottles. A typical 500-milliliter spray bottle of a ready-to-use interior cleaner is used up after one or two vehicles. With one liter of Mzr concentrate, you replace a significant number of these, with significantly less packaging waste and less space required in the trunk or on the shelf.

Anyone who regularly maintains several vehicles or works in a workshop will opt for the 11-kilogram canister. The resulting working volume at 1:20 amounts to over 200 liters of finished solution. This means many vehicles, several seasons — and a significantly lower price per liter of working solution than with the 1-liter version.

Users who have reviewed Mzr at Detailing1 highlight the combination of yield and cleaning performance as a key point. The product received 5 out of 5 stars on Trusted Shops, with comments such as "Very good cleaner that can also be diluted well" and "Super product. Very fair price." The Detailing1 shop as a whole has a rating of 4.53 out of 5 stars from 337 verified orders.

Soft-touch, leather, and painted surfaces: Where Mzr should not be used

If you use Mzr on the wrong surface, you won't notice it immediately - but you will after a few minutes. Soft-touch surfaces, such as those used in modern dashboards and door panels, are sensitive to strong alkalis. pH 12.5 can dissolve these surfaces. This manifests as altered haptics, discolorations, or a dull, matte appearance that cannot be reversed by normal cleaning.

Genuine leather reacts similarly. The natural fats in the leather, which provide suppleness and durability, are dissolved by strong alkalis. The result is a brittle surface that will crack over time. For leather, there are special cleaners tailored to this need. The Koch-Chemie Allround Leather Cleaner is an example: a cleaner specifically for genuine leather, synthetic leather, and vinyl that does not affect their protective properties.

Painted surfaces are also taboo. This applies to exterior paint, painted plastic parts in the interior, and aluminum parts coated with protective lacquer. The hazard warning H314 on the concentrate container is clear: the undiluted concentrate causes severe skin burns and serious eye damage. When refilling, gloves must be worn. When working near exterior paint surfaces, the solution should not drip or get onto the paint.

Caution is also advised for Alcantara and velour: The structure of these materials can be damaged by strong alkalis. Here, a test in an inconspicuous area and a stronger dilution are recommended before treating the entire surface. Detailing1 provides a separate overview for cleaning Alcantara seats.

Mzr or Green Star: When to choose which Koch-Chemie cleaner

Koch-Chemie offers two universal cleaners in its range, Mzr and Green Star, which at first glance sound similar. Understanding the difference helps you choose the right product and avoid mistakes when using them on sensitive surfaces.

The Green Star "Gs" is a universal cleaner with a milder pH value, designed for pre-wash and general exterior cleaning. It is compatible with paints, suitable for rims with normal dirt, and can be used regularly without stressing sensitive surfaces. If the car is to be pre-treated with an APC before the actual wash, Green Star is the right choice. The direct comparison of pre-wash methods is explained in the article Snow Foam or APC Pre-Wash.

The Mzr is intended for tasks where organic dirt has penetrated deeper: graying in fabric carpets after months without deep cleaning, nicotine film on the headliner, oil vapors in the engine compartment on plastic covers, heavily soiled door jambs. If Green Star does not show sufficient effect for a task, Mzr is the next step.

A practical decision rule for everyday use: If soft-touch, leather, or paint are nearby and you are unsure, use Green Star. If you are cleaning a clearly defined, hard surface and know that no sensitive material is within reach, Mzr can unleash its full potential. The difference is immediately visible after the first application for deeply ingrained organic dirt. Those who know both products will automatically reach for the right cleaner - without thinking.

Spring check: Which areas of the vehicle benefit most from Mzr now

In spring, anyone who takes their car seriously opens up the interior for a systematic cleaning after four months of winter. The classic problem areas are not just the seats and floor mats, but also the spots that are overlooked during a quick clean-up.

Door jambs are one such zone. Between the car body and the door rubber, grease, rubber abrasion, and road dirt accumulate from four winter months. Hardly visible from the outside, but a breeding ground for discoloration and corrosion. A 1:20 solution in a spray bottle, let it soak in briefly, wipe with an old cloth – this takes two minutes per door and shows immediate results. Vehicles handed over with clean entry areas look significantly more well-maintained than those where this area is neglected.

Entry areas and sills are classic road salt zones. The salt is water-soluble, but in combination with road dirt, it adheres particularly stubbornly. A 1:15 solution with a stiff brush quickly removes this combination. Afterward, wipe with clear water to ensure no residues remain.

Many people clean the trunk rubber mat and the trunk interior with water alone. Old grease stains are not completely removed this way. Here, the Mzr shows its strengths at 1:20: spray, let it soak in briefly, wipe off with a microfiber cloth. For a complete systematic approach – which product for which interior surface – see the overview article Interior cleaning: Which products for which material.

Anyone who maintains the vehicle with the engine compartment closed should also consider this: The door seals themselves – meaning the rubber profile around the door opening – benefit from rubber care after cleaning. This keeps the material elastic and prevents it from becoming brittle over the summer. When using Mzr, treat the rubber seals only briefly and with a heavily diluted solution (1:50), then wipe dry and then care for them.

Anyone using the Koch-Chemie Mzr for the first time for a spring check will find that one liter of concentrate is sufficient for the entire vehicle – and remains usable for the summer.

Detailing1 Insight: We use Mzr in the workshop as standard for door jambs and entry areas before every vehicle handover. What customers often don't see, but sense: If a sill is clean and the interior smells fresh, the entire vehicle appears more well-maintained. At 1:20, this is not an aggressive application. The difference compared to a cloth with water is still immediately measurable. We fill a small 100-milliliter spray bottle exclusively for this task and place it next to the disposable cloths. This saves time, and the result speaks for itself.