G'day - I see by another reply that it must be a corded, electronic mouse.  Can't help!

But I remember seeing the following years ago   -

I don't know how they wrote this with a straight face. This apparently was a real memo sent out by a computer company to its employees in all seriousness.

It went to all field engineers about a computer peripheral problem. The author of this memo was quite genuine. The word is that the engineers literally rolled on the floor! Especially note the last couple of sentences.

Re: Replacement of Mouse Balls.
If a mouse fails to operate or should it perform erratically, it may need a ball  replacement.

Mouse balls are now available as FRU (Field Replacement Units). 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.
Foreign balls can be replaced using the pop off method. Domestic balls are
replaced by 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 person have a pair of spare balls for maintaining
optimum customer satisfaction.

Any customer missing his balls should contact the local personnel in charge
of removing and replacing these necessary items.

Please keep in mind that a customer without properly working balls is an
unhappy customer.