This is an actual alert to IBM field engineers that went out to all IBM Branch offices. The person who wrote it was very serious. The rest of us may find it rather funny.
At least as old as 14-Jan-1992 17:41
Abstract: Mouse Balls available as FRU. ∞
Mouse balls are now available as FRU (Field Replacable Units). Therefore, if a mouse fails to operate or should it perform erratically, it may need a ball replacement.
Because of the delicate nature of this procedure, replacement of mouse balls should only be attempted by properly trained personnel. Before proceeding, determine the type of mouse balls by examining the underside of the mouse. Domestic Balls will be larger and harder than foreign balls.
Ball removal procedures differ depending upon the manufacturer of the mouse. Domestic balls are replaced using the twist-off method. Mouse balls are not usually static sensitive. However, excessive handling can result in sudden discharge. Upon completion of ball replacement, the mouse may be used immediately.
It is recommended that each replacer have a pair of spare balls for maintaining optimum customer satisfaction and that any customer missing his balls should suspect local personnel of removing these necessary items.
To re-order, specify one of the following:
P/N 33F8462 - Domestic mouse balls
33F8461 - Foreign mouse balls
ported