When to clean your mouse
When an optical mouse needs cleaning, the mouse pointer's movement will be sporadic, it may also jump across the screen for no reason.
When a mechanical mouse (ball mouse) needs cleaning, you will notice the mouse pointer sticking in one position while you are moving it.
To clean a mouse is fairly straightforward, it only takes 10 minutes for a ball mouse, and even less time to clean an optical mouse.
Basic Mouse Operation
First, to understand what is happening when your mouse gets dirty, and clarify which parts will need cleaning, a brief word about how the different types of mouse work.
How an optical mouse works
An optical mouse uses light to track the movement of the mouse. An LED (Light Emitting Diode) produces light which reflects back into a light sensor (Photodiode). The differences in the surface below the mouse lens are scanned, as the mouse moves, the surface changes, the direction is calculated and the movement is simulated by the mouse pointer.
If any foreign object, such as a hair or piece of dust, were to disturb the communication of light between the LED and the sensor, it would result in very unexpected behaviour!
How a mechanical mouse (ball mouse) works
As you move the mouse on a flat surface, the ball inside turns a set of 3 rollers. Each roller is set at a different angle to its counterparts, as the rollers are turned, signals are sent to the computer. The computer then interprets these signals into the movement of the mouse pointer on your screen.
For this reason, it is important to keep the rollers and the ball inside your mouse clean, any piece of dust/debris, no matter how small, can make your mouse behave abnormally.
How to clean an optical mouse
Although optical mice usually require far less maintenance than their mechanical counterpart, they do need cleaning once in a while.
To clean an optical mouse should take less than 5 minutes, so giving it a quick clean every month should be achievable, which will help ensure it keeps working smoothly.
The first step is to unplug your mouse. Optical mice usually connect to the computer via the USB port, if you have a USB mouse then you can remove it without switching off the computer. If, however, your mouse connects using a different connector, then you should switch your computer off first.
Once unplugged, look at the bottom of the mouse to locate the area where the LED and the lens is located.
Dampen the end of a cotton bud with a few drops of suitable cleaning fluid, never put fluid directly onto the mouse. Take the damp cotton bud and gently wipe the area to remove any dust or residue, be very careful not to put any pressure on the LED or lens, and also, ensure that no excess fluid gets squeezed out of the cotton bud into the mouse. You may find turning the cotton bud between your fingers can be effective. Once done, use a dry cotton bud to gently wipe over the area to ensure it is dry.
How to clean a ball mouse (mechanical mouse)
First, turn off your computer (unless you have a USB mouse) and then unplug your mouse. Get to hand a soft tissue, along with some suitable cleaning fluid (window cleaner is fine).
Use the soft tissue to clean the mouse ball, be sure to remove all dust/hair/debris.
You can improvise on how to clean the rollers, gently using your fingernail can get good results. Whichever way you choose to clean them, make sure you remove all traces of dust/debris, as the smallest piece can cause the mouse to behave erratically.
When you have removed all traces of dust/dirt from the rollers, and the ball is nice and clean, simply put the ball back in and replace the cover, turning clockwise to lock it in place.
Plug the mouse back into your computer and your mouse should be as good as new.