Cleaning the CPU

Look at the rear of the main PC box (either your desktop or tower case). You will see a grated circular (or in some cases square) hole covering a fan. Is the grating clogged with dust, dirt, hair or other foreign material? If so, your CPU is most likely in need of cleaning. Internal PC cleaning with compressed air should only be performed by an experienced technician, as air pressure applied to certain areas of the PC can cause damage. An example of this is the CPU fan. The CPU fan is attached to a heatsink to cool the CPU. It will accumulate a great amount of dust over time, as it is electromagnetically charged (similar to the power supply, video card, modem, etc.). Forced air applied to a free-spinning fan can damage the bearings in the fan, causing it to stop spinning. If cleaning a fan with forced or compressed air, make sure to keep the fan from spinning freely - block the blades with a small screwdriver or similar object while cleaning.

The outside of the case can be cleaned with an all-surface cleaner such as Formula 409 or Windex. DO NOT DIRECTLY SPRAY CLEANERS ONTO THE CASE. Rather, spray the cleaner on a lint-free towel, then wipe down the front and sides of the case, taking special care to avoid the operating doors of the CD-ROM, floppy drive and any other bay-mounted devices.

DO NOT SPRAY COMPRESSED AIR INTO THE CPU, FLOPPY OR CD. This can damage or misalign the internal components, causing the drive to fail when reading media. Do not spray compressed air into the case / power supply at the rear of the CPU. The dust you see accumulating on the rear fan grate was drawn through vents at the front of the PC, traveled through the PC (depositing some on the internal components) then was drawn through the power supply and pushed out the rear. If you blow dust into the case, there is more to accumulate on the expensive components inside the PC. Internal dust and other foreign material can cause overheating and eventually will lead to component failure.

Cleaning the Monitor

Turn the monitor off and unplug it before cleaning. Again, do not spray cleaner directly onto the monitor. There are vents in the monitor housing to allow for heat dissipation. Liquid cleaner on the internal monitor components can cause damage, so use the method of spraying cleaner on the towel then wiping down the monitor.

Cleaning the Keyboard, Mouse, Scanner

As with all the procedures explained here, make sure the PC is turned off while cleaning. The keyboard should be cleaned like the monitor and case exterior - wipe it down with a pre-sprayed towel, do not spray cleaner directly on the components.

A mouse may need to be internally cleaned if performance is spotty or erratic. Turn the mouse over and look at the bottom. A standard mouse will have an internal ball in the base which usually activates either a horizontal or vertical switch. Sometimes dust and other materials will accumulate on the rollers or the ball itself. The ball is usually held in with a circular plate that can be removed. Once the ball has been removed, blow out any foreign material. Look inside at the rollers. If they have dirt accumulated on them, this can be removed using a q-tip and rubbing alcohol. Be careful to use the alcohol sparingly. The ball should be cleaned with a lint-free towel and all-purpose cleaner. DO NOT USE CLEANERS WITH ABRASIVES ON ANY COMPONENTS! Reassemble the mouse and it should return to normal operation.

Scanners should have the scanning glass surface cleaned occasionally - perform a visual check when you are using the scanner. Foreign objects, dust and other contaminants can be detrimental to your image quality. Smudges from fingertips, specks of white-out, traces of printer or pen ink from scanned originals can all cause imperfections in your scans. Clean the glass surface with a lint-free towel and glass cleaner, and the exterior with an all-surface cleaner.