A. The TFT or LCD screen is one of the most expensive components of your notebook or desktop computer and they’re very tricky to dust, since the sensitive display is likely to get scratches from dust particles.
Never use glass cleaner to clean LCD screens and do not use tap water or mineral water as this could leave white marks on the screen due to the dissolved salts. Turn the monitor off to help identify the dirty areas of the screen. A soft, dry and clean cloth can be used to gently dust the screen, but for cleaning heavier dirt, screen cleaning wipes designed specifically for LCD screens should be used (the same should apply to HDTVs and plasma TVs as well). Taken from http://labnol.blogspot.com/2006/11/wipe-clean-lcd-screen-laptop-monitor.html