2003 GMC Sonoma Owner's Manual - Page 200

For best results, use a scrubbing action, non-abrasive cleaning cassette with pads which scrub the tape head as the hubs of the cleaner cassette turn. The recommended cleaning cassette is available through your dealership. The broken 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. After the cleaning cassette is ejected, the broken tape detection feature will be active again. 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 EJT button for five seconds to reset the CLEAN indicator. The radio will display 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 you have your tape player serviced. 3. Press and hold the TAPE CD button for five seconds. READY will appear on the display and a cassette symbol will flash for five seconds. 4. Insert the scrubbing action cleaning cassette. 5. Eject the cleaning cassette after the manufacturer's recommended cleaning time. 3-73