When you first purchased your flat screen HDTV, the screen was clean and gave you the best possible picture. Over time, the screen accumulates dust like any other household item. Whether you have a plasma or LCD HDTV, you need to be careful with what products you use to clean the screen, as using the wrong chemicals can cause permanent damage.
Check your HDTV's manual for any specific cleaning instructions. Television screens are not always the same and the manufacturer of your set might have specific recommendations. If the manufacturer suggests a particular cleaning product, use that. Do not use any chemical that the manufacturer warns against.
Dampen a soft cloth with water, if the manufacturer does not recommend specific products or chemicals. Do not use anything rough, like a paper towel. A microfiber cloth or old, soft T-shirt are ideal. Wring out the cloth to remove any excess water.
Wipe the screen with the damp cloth. Do not press hard as that may damage the screen. If the screen does not dry immediately, wipe it down with another soft cloth.