IBM Memo about Peripheral Replacement
   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.
   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 maybe 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.