Sort Out an Erratic Mouse

Your mouse will be one of two types, an 'Optical' mouse which has a light underneath when you lift it or a 'Ball' mouse.

Optical Mouse

There is no maintenance which can be carried out on an Optical mouse, other than changing the battery on a wireless device when the light doesn't come on any more.
Consider the surface you are working on. An Optical mouse works by detecting reflections of its light and is best used on a matt surface. It will happily work on a table cloth, arm of a chair but it won't work accurately on a reflective surface so a glass or highly polished surface should be covered with something non-reflective.
Mouse mats and backs of magazines with high contrast black and white patterns can also cause trouble.

Ball Mouse

If you have an old type mouse which has a ball underneath you may find that your mouse pointer doesn't move smoothly or accurately after some time. A couple of minutes will often restore it to as good as new.

The Ball mouse works by the ball, which rolls in different directions as you move the mouse across a flat surface, making contact with 3 rollers inside the casing. These rollers pick up grease and dust from surfaces and eventually this affects the contact. Removing this residue allows the rollers to once again make good contact with the ball.

WARNING: Do not remove any screws from the mouse casing. There are springs inside the assembly and re-assembly can be difficult.

1. Turn your mouse over so the ball is on top.
2. Look at the circular section of the base around the ball, you will see 2 arrows indicating a direction to turn.
3. Now place two fingers onto the ridged areas and twist the circular retainer in the direction indicated.
4. The circular retainer will pop out and release the ball. Upturn the mouse and drop the ball out into your hand.
5. Examine the inside through the hole and identify 2 horizontal rollers and one vertical roller which is on a sprung assembly. If they need cleaning you will see a line of residue around the horizontal rollers and along the centre of the vertical roller.
6. Use a small knife or a finger nail to gently scratch off the residue rolling the rollers with each scratch until all the residue drops off.
7. Turn the mouse hole down and blow out any junk.
8. Finally, give the ball a wipe over and drop it back into position.
9. Reposition the retaining ring positioning the lugs in the gaps and twist the opposite direction from the arrows to lock.

I have uploaded a video to YouTube showing this process here: http://youtu.be/im9ZUryfdAo