What is the best way to clean the screen of a iPad that does not have a screen protector overlay? My first unit had a protector applied at the time of purchase so I never got the "feel" of using one without a protector. Now using a new iPad I really like the look and especially the feel of the touch action without a protector but.... What is the best way to clean it so as not to loose the feel of whatever is coating the screen. It feels slipperier than a overlay and does not fingerprint much. I don't want to apply something that will take that away. Thank you !