Clean the document glass once a month to maintain image quality of the printouts.
Do not use benzine, thinners, or alcohol. They may damage the plastic parts of the machine.
If the document glass surface and document holding pad are very dirty, wipe gently with a soft cloth that has been moistened with neutral detergent and squeezed well, and then wipe again with a soft cloth that has been slightly moistened with water and squeezed well.