See also:

Cleaning the wheels
Do not use acidic wheel cleaning products to remove brake dust. This could damage wheel bolts and brake components. Do not park the vehicle for an extended period straight after cleaning ...

Cleaning the steering wheel and gear or selector lever
Thoroughly wipe with a damp cloth or use leather care agents that have been recommended and approved by Mercedes- Benz. ...

Immobilizer
The immobilizer prevents your vehicle from being started without the correct SmartKey. When leaving the vehicle, always take the SmartKey with you and lock the vehicle. The engine can be started ...