Scholl Concepts RIM-7 is a smart, acid-free cleaner with colour-change technology for the effortless cleaning of extra dirty wheels. The high viscosity ensures that RIM-7 sticks to the area applied. The smart “colour-change-formula” converts the colour of the cleaning gel to purple after the ideally recommended exposure time has elapsed (2 to 3 minutes) and shows the user that the wheel can now be rinsed off with water.