Smudges, Finger Prints and Dust are not something you want on your LCD or Plasma Screens. To have an ideal viewing experience you will need to keep your screen clean. You can't just scrub your TV with anything, you need to be careful, because the coatings on screens is often pretty delicate. Remember if you scratch your TV, it's there for life. But if you protect your TV, it will last and look new for a long, long time.
Step 1: Prep the Cloth
To properly clean an LCD or plasma TV, only use a microfiber cloth, which you wash before the first use, in cold water and NO SOAP and then air dry. You don't want any residues on the cloth that could leave build up on the TV, and the detergents in soaps can break down the anti-static and glare coatings on a display.
Step 2: Clean But Not With a Window Cleaner
If you want to use a liquid to clean the glass, make sure you know if you have a glare or non glare surface and pick the appropriate cleaner from an optical supplier, try not to get anything off the shelf. Anything off the shelf could change the glare and the polarization. Cleaners meant for eye-glasses, and TV screens can be ok, but you NEVER want to use Windex, Counter Cleaner, or a Window Cleaner as it can damage the coating.