There comes a time, after a period of use that your mouse ball becomes, well, er, filthy... (Cue Butthead...)
So, sometimes you just have to take matters into your own, er, hands...
The first rule when performing a procedure this delicate is to have a nurse in the room, hopefully a nurse with the proper empathy.
So, with the proper witness to forestall any funny business or protracted lawsuits, it's time to get down to business:
The mouse balls in this particular mouse are very small and quite hard to get to, but the operation was a success!