I think you are just meant to blow the dust off with a can of compressed air or something and not wipe it with anything.
Lifted from another website -
I know alot of people use rags, paper towels and the like on LCD's but be warned this is not good.
The Liquid Crystal Display is extremly delicate.
1.) Never touch the screen for 2 reasons.
a. You will kill pixels and leave permanent black spots.
b. You will leave fingerprints
2.) Never wipe anything across an LCD screen, it will scratch the screen and you are applying pressure to it.
3.) If you never touch it then the only thing on the screen is dust. If you use canned air and blow it off from the side you should have a clean screen again. NEVER blow on the screem from the front as this will damage the screen.
4.) Do not use a feather duster or vaccume to dust the LCD screen, this can scratch the screen
5.) I am sure there is more but I can think right now, my brain hurts. Stupid alcohol