I’m sure that, like me, you’ve tried all kinds of chemical cleaners to clean LCDs. But, like me, also, you’ve noticed most of them leave smudges that you can’t get rid of. Window Cleaners are also rather bad at this, and they may be too rough for the coating of your LCD screens.
However, I think I finaly found what it takes: 50% isopropyl alcohol. That’s right, common rubbing alcohol you can get for 3$ at your local drugstore. Even better, they sell it with a spray cap, for your convenience. Just spray alcohol on a clean, soft, non-linting rag (like a paper towel) and clean your screen gently. Do not spray at the screen directly, because it may cause some of it to leak into the electronics and cause much mayhem. It may take a few application to remove all of the previous chemical cleaner’s residues… but I haven’t seen my screens that clean in a long time.