Directly from device manual :
On Cleaning
Unplug the display before cleaning the face of the display screen.
Use a slightly damp (not wet) cloth. Do not use an aerosol directly on the display
screen because over-spraying may cause electrical shock.
When cleaning the product, unplug the power cord and scrub gently with a soft
cloth to prevent scratching. Do not clean with a wet cloth or spray water or other
liquids directly onto the product. An electric shock may occur. (Do not use
chemicals such as benzene, paint thinners or alcohol)
Spray water onto a soft cloth 2 to 4 times, and use it to clean the front frame; wipe in one direction only. Too much moisture may cause staining.