"Memo of the Month," From The Washington Monthly, January/February 1991,
page 24:

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
guys find it rather funny.
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Abstract: Mouse Balls Available as FRU (Field Replacement Unit)

Mouse balls are now available as FRU. 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 manufacturer
of the mouse. Foreign balls can be replaced using the pop-off method.
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
P/N 33F8461 - Foreign Mouse Balls
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