Pontiac 2003 Montana Owner's Manual page 264

The cut tape detection feature of your cassette tape
player may identify the cleaning cassette as a damaged
tape, in error. To prevent the cleaning cassette from
being ejected, use the following steps:
1. Turn the ignition on.
2. Turn the radio off.
3. Press and hold the CD TAPE button for five
seconds. The tape symbol on the display will flash
for two seconds.
4. Insert the scrubbing action cleaning cassette.
5. Eject the cleaning cassette after the manufacturer's
recommended cleaning time.
After the cleaning cassette is ejected, the cut tape
detection feature will be active again.
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You may also choose a non-scrubbing action, wet-type
cleaner which uses a cassette with a fabric belt to
clean the tape head. 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 you clean the player, press and hold the eject
button for five seconds to reset the CLEAN PLAYER
indicator. The radio will display --- 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 you have your tape
player serviced.