B&K Precision 830C - Manual - Manual (Page 109)

107
Before cleaning this meter, make sure the power is
OFF and remove external AC adapter if one is used.
To clean the meter, wipe the dirty parts with a soft
cloth soaked with diluted neutral detergent. Avoid
having the instrument too wet to prevent the detergent
from penetrating into the inside components of the
meter, causing damages. After cleaning, make sure
the instrument is completely dried before operating it
again.