Apple LaserWriter 12/640 PS - Manual (Page 223)

8 Close the printer and resume printing.
Cleaning the exterior
Unplug the power cord and then wipe the exterior of the printer with a clean,
soft, damp cloth. Use a mild soap or detergent if necessary, but
never use
an ammonia-based cleaner. Be careful not to get any liquid in the power
cord port.
WARNING Never use ammonia-based cleaners on or around the
LaserWriter 12/640 PS. They may react chemically with the toner
and with the printer’s plastic case.
224 Chapter 10