I don't know when Apple finally "came clean," but after years of agonizing over what to use to clean my display and never being satisfied with my results no matter what I decided on, I've finally found a definitive Apple doc.

70% isopropyl alcohol! Cheap, readily available, and will not damage your display as I've always feared it would.

Good to know. FYI, in broadcasting, back when tape ran across audio and video heads, those heads were always cleaned with isopropyl alcohol.

I use a microfibre cloth sprayed with a little water (misted, not soaked) when the computer is Shut Down and the computer glass is cool to the touch. Lifts every icky off the screen and leaves no streak marks.

Sounds like your display is more or less as "dirty" as mine, but you ought to see some of the others!

The imagination just runs wild!