This Apple Cleaning Cassette was included with Apple Workgroup Server models equipped with a DDS DAT drive. DAT, Digital Audio Tape, was a generic term used for all 4mm audio and data tapes. DDS, or Digital Data Storage, drives could store 2GB–18GB of data on a 4mm tape housed in a mini-cassette (depending upon the version of the DDS and capacity of the tape).
Apple Workgroup Servers that shipped with an optional internal DDS-2 DAT drive included one of these cleaning cassettes. According to Apple’s user manual:
“When you insert the cleaning cassette into the drive, the drive automatically loads it and cleans the heads. When the cleaning process is completed, the drive automatically ejects the cassette. Keep a record of how many times you use the cleaning cassette. After 25 uses, replace it. The interval at which you clean the tape drive depends on how often you use it. In general, if you back up daily, you should clean the drive weekly. If you back up weekly, you should clean the tape drive once a month.”
This quote is sourced from Apple’s User Manual for the Workgroup Server 8550 from 1996.
Sources: Apple, Apple History, 4crawler