The first thing you should do is turn off your TV and unplug it at the wall. Use a dry, anti-static cloth to remove any dust or loose dirt. For any harder stains use a lightly dampened anti-static cloth and gently rub the screen, then use a dry cloth to wipe it dry. Water should not run down the screen or enter behind it. Make sure to rub as gently as possible and never use any abrasive cloths or cleaners as you can scratch the screen or dissolve special coatings.