Has anyone had any experience using a Shark 250 on a TP760XD? Also, I need some advice on cleaning the screen of my 760XD. IBM Tech Help said there wasn't anything I could use on this 12.1 Active Matrix screen. Something has evidently splashed on it---I have drop marks in several places. Used a Gonzo Dry sponge but it didn't remove the marks. Any advice would be appreciated.