A good friend has a new Sony HDTV ready RPTV with a protective plastic screen cover. He has asked me how to clean it after it gets dusty. He has had many responses from Windex to soapy water to computer screen cleaner from various salespeople. He has yet to get a response from Sony HQ. Searches in forums has given me the same various answers... I do not want to steer this gut wrong after a $3000 investment. Is there difinitive answer on how to PROPERLY clean these screens without fading, scratching or yellowing?