this tip has been taken from pcmag.com
Even our high-tech machines are subject to everyday dirt, dust, and even greasy fingerprints. Any exposed parts can suffer because of dirt; PCs run hotter, monitors grow dimmer, printers jam, keyboards stick, and scanners deliver scratchy images. But what cleaning methods are both effective and safe? What should you apply when the user manual says "nonalkaline cleanser and a lint-free cloth"? Is Windex or Formula 409 okay? Can you use an old T-shirt? A damp paper towel? Here's an overview of how to keep your computer and peripherals clean.
You can do most cleaning with a microfiber cloth (such as those sold to clean eyeglasses and camera lenses) and warm water applied to a clean, all-cotton T-shirt or a second microfiber cloth. Dry microfiber cloths remove dust and finger oils from glass and other surfaces. Stains require a water-dampened cloth. (Warm water should always be the first liquid cleanser you try.) When the cloth gets dirty, wash it, and rinse it well. Avoid most paper products; facial tissue, paper towels, and toilet paper contain cellulose, which is scratchy, while products such as Kleenex Cold Care contain oil that soothes your nose but streaks everything else.
Most cans of compressed air are really compressed gas (and called that). Some are Freon substitutes (but less damaging) with some ability to dissolve grime. Hold the cans upright, and don't breathe the gas.
A CRT's glass face may be coated, and LCD faces are plastic, so they can be delicate. Clean first with a dry microfiber cloth. (A monitor-cleaning brush works for dust.) For persistent grime use a microfiber cloth dampened with water, followed by a dry one. Avoid ammonia-based cleaners such as Windex. Antistatic wipes can help with CRT displays, though today's CRTs have much less static than those sold a decade ago. Vacuum the vents to remove dust; don't use compressed gas to blow dust in.
Be wary of display-cleaner sprays and wipes. Some are not safe for certain monitors, but unfortunately manufacturers don't give model-specific cleaning instructions.
Almost any cleaner that doesn't dissolve the finish or leave scratches is fine for the average PC case. Laptop cases require gentler cleaning with a microfiber cloth or with cleaning wipes (sold by Belkin, Falcon, Kensington, and others). Vacuum your PC's air ducts; don't use compressed gas and never use a commercial air compressor. Vacuum the keyboard lightly or use a cleaning wipe; rub gently so you don't pop off (or vacuum up) a keycap and its spring.
To clean the inside of a PC, turn off the power, then pull the power cord. Ground yourself by touching a water pipe, radiator, or the center screw on the wall outlet first. Vacuum gently and carefully; a plastic vacuum-cleaner nozzle can discharge static. Blowing residual dust out of the case innards can keep heat sinks and other parts clean, but don't shoot compressed gas from an inch or two away, and never shoot it into a drive opening. Use cleaning disks ($10) on dirty optical and floppy disk drives.
Use a dry microfiber or lint-free cloth moistened with water or a mild glass cleaner on flatbed scanners. (HP says isopropanol- and butoxypropanol-based cleaners like Cinch, Spic And Span, Sparkle, and Glass Plus are okay.) Cleaners with ammonia or isopropyl alcohol may leave streaks. Cleaners with abrasives, acetone, benzene, or carbon tetrachloride may damage the glass. Only a few flatbed scanners let you clean the underside of the glass.
Sheet-fed scanners can be gently vacuumed to remove paper lint. You can also use fax, ADF (automatic document feeder), or scanner-cleaning sheets; run these sheets through a couple of times. With some, you moisten the fuzzy sheet with an included cleaning liquid first. Higher-end sheet-fed scanners and printers let you replace slipping rollers; for the others, wipe the rollers with a cloth soaked in pure rubbing alcohol (clear, not green). If you can reach the scanning elements, clean them with a microfiber cloth; using compressed gas might leave a slight residue.
Most print quality problems are cured with new toner or ink cartridges. But if your cartridges are fairly new and your output is still subpar, try these steps. On ink jets, run the light cleaning cycle, then the deep one. Clean laser printers with laser-specific cleaner sheets. If toner spills on your clothes, brushing it off and washing them in cold water might save the garments.
Vacuum the rollers and housings of roller-ball mice, or use compressed gas. Clean the glides on optical mice with rubbing alcohol. Cleaning wipes are fine for the bodies of mice, printers, and cables.
Spray compressed gas into jacks and plugs. Never lick or moisten jacks to improve electrical contact: It helps for a few minutes, but leads to corrosion.
Antistatic sprays applied to carpets and drapes may keep dust from clinging to computer devices. Use commercial sprays or mix water with fabric softener in a 2:1 ratio.
If your first pass at cleaning doesn't unstick a keyboard or make a floppy disk work, it's probably time to buy a new one. This also goes for CD or DVD read-only drives, mice, sub-$100 printers, and older flatbed scanners. Today's low peripheral prices often make replacement the best option. But cleaning regularly (and at the first sign of any dirt build-up) will make any peripherals, as well as the PC itself, last longer and run better.