GMC 2007 Sierra - Manual (Page 352)

A non-scrubbing action, wet-type cleaner which
uses a cassette with a fabric belt to clean the tape
head can be used. This type of cleaning cassette
will not eject on its own. A non-scrubbing
action cleaner may not clean as thoroughly as the
scrubbing type cleaner. The use of a
non-scrubbing action, dry-type cleaning cassette is
not recommended.
After the player is cleaned, press and hold the
eject button for five seconds to reset the CLEAN
indicator. The radio will display --- or CLEANED to
show the indicator was reset.
Cassettes are subject to wear and the sound
quality may degrade over time. Always make sure
the cassette tape is in good condition before
the tape player is serviced.
Care of Your CDs and DVDs
Handle CDs carefully. Store them in their original
cases or other protective cases and away from
direct sunlight and dust. The CD player scans the
bottom surface of the disc. If the surface of a
CD is damaged, such as cracked, broken,
or scratched, the CD will not play properly or not
at all. If the surface of a CD is soiled, take a
soft, lint free cloth or dampen a clean, soft cloth in
a mild, neutral detergent solution mixed with
water, and clean it. Make sure the wiping process
starts from the center to the edge.
Do not touch the bottom side of a CD while
handling it; this could damage the surface. Pick up
CDs by grasping the outer edges or the edge of
the hole and the outer edge.
Care of the CD and DVD Player
The use of CD lens cleaners for CDs is not
advised, due to the risk of contaminating the lens
of the CD optics with lubricants internal to the
CD mechanism.
352