Koch Chemie MZR Mehrzweckreiniger is a strongly alkaline intensive cleaner that tackles oil, grease, soot, nicotine and road dirt. You dilute it to the weight of the job, apply it to a cool surface, let it dwell briefly and wipe it off. Neat, MZR is corrosive, so you work with dilution and gloves. You will find the Koch Chemie MZR Mehrzweckreiniger in the shop.
What MZR does
MZR is a powerful cleaner for stubborn, ingrained dirt. Koch Chemie states that the cleaner has a pH of 12.5 and is Daimler-approved. It is meant for alkali-resistant materials: carpet, upholstery, headliner, plastic and industrial machines. For sensitive or untreated surfaces it is too strong; for those you choose a mild, near-neutral cleaner.
Diluting to the job
Koch Chemie uses a dilution range of 1:5 to 1:50 for MZR, depending on how soiled the surface is. For heavy grease you work more concentrated (towards 1:5), for lighter work more diluted (towards 1:50). When in doubt start with a weaker dilution and work up.
How to use it
Dilute. Mix MZR with water in the ratio that suits your job, between 1:5 and 1:50.
On a cool surface. Apply the solution with a spray bottle or microfiber cloth to a cool, not hot surface.
Dwell and agitate. Let it dwell briefly and work stubborn dirt with a brush or cloth; do not let it dry.
Wipe off. Wipe the residue with a damp cloth or extract it with a wet-dry vacuum.
What to watch for
Neat, MZR is corrosive, so wear gloves and eye protection and use it diluted. Work on a cool surface, not on a hot panel or in full sun, and do not let the product dry. Only use it on alkali-resistant materials. For a universal, widely dilutable all-rounder you can also look at the Koch Chemie Green Star. Which APC suits which job is in the guide using and diluting all-purpose cleaner (APC).