Computer mice tend to attract muck. Sooner or later this muck accumulates
inside the works and the mouse becomes difficult to use, with the
mouse pointer moving unpredictably on the screen.
When this happens it's time for a bit of mouse cleaning. Not all mice
are constructed in the same way, but generally the following procedure
1 With the computer turned off, turn the mouse over (you don't normally
need to unplug it) and you will see the ball, surrounded by a circular
plastic disc - like a small plastic manhole cover.
2 Hold the mouse with both hands and, using both thumbs, press lightly
on the plastic disc and free it by rotating - usually anticlockwise.
(Sometimes there will be an arrow marked on the bottom of the mouse,
indicating which way to turn to open it)
3 Once you have freed the disc, hold one hand over it and turn the
mouse back the right way up. The disc and ball should fall into your
hand. Put them safely to one side where you won't lose them.
4 Flip the mouse over again and peer inside. You should (usually)
see three moving parts:-
A small spring loaded wheel, and two small plastic rollers at right
angles to each other.
The small wheel provides some thrust to the ball to keep it in contact
with the two rollers.
You will probably see a build up of dust and fluff in the centre of
each roller, and there may be some on the small wheel. This needs
5 Cleaning can be a bit fiddly, and you need to be careful. The roller
assemblies are not very robust, so don't press too hard when cleaning.
or something may break. You can gently remove the worst of the buildup
with a sharpened matchstick, or the blade of a small knife, carefully
scraping sideways, and turning the roller a little at a time until
the muck is removed all round. Some of the muck may fall back inside
the mouse if you're not careful; if this happens give it a good blow
out at the end.
6 When the mechanical cleaning's done, a rub with a cotton bud moistened
with meths can be used to remove the last of the buildup from the
rollers. Check that they turn freely, and that you've cleaned right
round the circumference.
Also check the ball before reassembly - if there' any obvious dirt,
7 To reassemble, hold the cover disc with the ball in its centre in
the palm of one hand, and place the body of the mouse over it. Then
invert the mouse (the ball falls inside), and fasten the disc in place
by turning it in the opposite direction to the one you used to remove
Simple, isn't it!
John Selby - Technical Manager
First printed in SNN Newsletter March-April 2001