See also:

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. ...

Important safety notes
WARNING On slippery road surfaces, never downshift in order to obtain braking action. This could result in drive wheel slip and reduced vehicle control. Your vehicle's ABS will not prevent ...

Mechanical key
General notes If the vehicle can no longer be unlocked with the SmartKey, use the mechanical key. If you use the mechanical key to unlock and open the driver's door, the anti-theft alarm system ...