The head of your light is comprised of two different parts. The purely cylindrical part with the reflector lens and the Rapid Focus carriage which tapers off into a tube. In some newer models the cylindrical part is silver.
2. Unscrew the cylinder from the Rapid Focus carriage in anticlockwise direction.
3. Please note that you should NEVER TOUCH THE LED.
4. Remove the Rapid Focus carriage from the light downward. Now you can properly clean all of the parts from the inside with a damp or dry cloth. You can treat the O-ring which can now be seen on the light compartment with silicon-free grease.
5. Then re-close the head of the light by again pulling up the Rapid Focus carriage and screwing it back together with the cylindrical part. In all models with a Focus Lock function you have to pay particular attention to one thing when pulling up the carriage. The grooves on the inside of the carriage have to slide exactly along the tracks that are intended for that purpose.