Cleaning
*Warning: Liquids penetrating the casing can damage or destroy the device.
Only clean the device with a dry cloth.
To clean without accidentally selecting or activating functions, the phone can be put into cleaning mode.
The cleaning mode is enabled via a function key for 60 seconds. During this period
every press of the key is ignored
if do not disturb is enabled
*Caution: Dialing an emergency number is not possible in cleaning mode.
Configuration
Web interface: 
Function keys > Choose a key > Function: Cleaning
*Details about the settings are in Function keys
Phone: 
Settings > Function keys > Choose a key > Function: Cleaning
*Details about the settings are in Function keys
Provisioning: 
*Further help in the Auerswald DokuWiki