User`s guide

Cleaning Information Cleaning Instrument Housings
92 Agilent 81618A/9A and Agilent 81623B/4B/6B/8B Optical Heads, Fourth Edition
Cleaning Instrument Housings
Use a dry and very soft cotton tissue to clean the instrument housing and
the keypad. Do not open the instruments as there is a danger of electric
shock, or electrostatic discharge. Opening the instrument can cause
damage to sensitive components, and in addition your warranty will be
voided.