See also:

Headlamp cleaning system
The headlamps are cleaned automatically if the "Wipe with washer fluid" function is operated ten times while the lights are on and the engine is running ...

Service and literature
Your vehicle is covered under the terms of the warranties printed in the Service and Warranty Information booklet. Your authorized Mercedes-Benz Center will exchange or repair any defective parts ...

Cleaning the exterior lighting
  Clean the plastic lenses of the exterior lights with a wet sponge and a mild cleaning agent, e.g. Mercedes-Benz car shampoo or cleaning cloths. Only use cleaning agents or cleaning ...