IBM 3590 - Manual (Page 89)

automatically cleans, when a *CLEAN message is displayed, load a cleaning
cartridge in the drive. The cleaning cartridge will complete its cycle and then
unload.
Cleaning Notification
Two types of cleaning notification are available:
v Operator Panel Cleaning Notification
v SCSI interface cleaning notification
The sections that follow describe each type of notification.
Operator Panel Cleaning Notification
When the 3590 determines that it needs cleaning with a cleaning cartridge, it
generates a Clean message. The operator panel displays the Clean message
when a cartridge is unloaded.
SCSI and Fibre Channel Interface Cleaning Notification
When the 3590 determines that it needs cleaning with a cleaning cartridge, it
generates SCSI Request Sense and Log Sense data. For more information, refer
to IBM 3590 High Performance Tape Subsystem Hardware Reference Manual.
Chapter 5. Cleaning Procedures 69