Sonax Wheel Cleaner Plus is acid-free, pH balanced formula is safe on all wheels and won't damage wheels. Safe on various wheel finishes including: Chrome, Aluminum, Steel, Clear Coated, PVD, Painted, Plastic Wheel Covers, Magnesium, AND Aftermarket Wheels. Watch the color changing activate when it comes in contact with the ferrous metals (iron) from brake dust or other dirt and grime. Wheel Cleaner Plus sprays on clear, then turns deep red or purple as it dissolves brake dust. The advanced and effective chemistry in Wheel Cleaner Plus attaches and emulsifies stubborn baked on brake dust. Simply spray on, let it dwell, watch for color change, agitate if necessary, and rinse with water. For best results rinse using high pressure water. Wheel Cleaner Plus is an extra strength formula for European cars with difficult to clean wheels due to the high heat and brake dust. Sonax Wheel Cleaner Plus is ideal for all vehicles including Mercedes, Audi, BMW, Volvo and many others. Effortlessly achieve shining wheels that will make your vehicle look like it just rolled off the showroom floor. Wheel Cleaner Plus needs to be used on cool and dry wheels. Product is ready to use, do not dilute with water. *Use caution when applying this product to anodized wheels and brake systems - test in an inconspicuous area prior to use. Use Sonax Wheel Cleaner Plus to safely clean dirt and brake dust on hard to reach wheel barrels and calipers, too.