...I've tride normal glass cleaner
Never use Windex or equivalent products.
If additional cleaning of the display panel or case is required use a soft, slightly damp, lint-free cloth. Avoid getting moisture in openings. Don’t use window cleaners, household cleaners, aerosol sprays, solvents, alcohol, ammonia, or abrasives to clean the display.
Just use plain warm water and a good quality microfiber cloth. That's all you need.
Dampen the cloth (damp only, not wet) and use it to wipe the screen from one side to the other. Work your way down the screen one pass at a time. Refold the cloth every pass or two, depending on how dusty your screen is.
NEVER use Windex or any other general purpose glass cleaner. And never spray the screen with any liquid, including water. For what it's worth, you don't need special cleaners like iKlear, either. A damp microfiber cloth works best.
Everyone has their own preferences. I do it in sections with a damp Qtip--not so wet it runs-- only on a small area of the screen, then clean and dry that small area with a microfiber cloth. I use the small black one that Apple provides. I've found it's better even than the ones you can get with glasses.
unfortunately I have also used glass cleaner, no damage as far as I can see, did it weekly on my old iMac, too...looked brand new when I sold it, but I agree; the black cloth provided with the new iMac is better to remove stripes than any other types of cloth, I'll use what Apple recommend after reading this :)
" Never use Windex or equivalent products."
I'll second this suggestion. When I first cleaned my new 2013 21.5" iMac, I used
a "windex" type cleaner, and it made a mess (streaked and everything). I actually though it was so bad that I had damaged the screen. Fortunately, with water and a microfiber cloth I was able to clean off the "windex" streaking.
The thing is, the new 2013 iMac screen covering is more "plastic like" in material, and not as "glass like" in materials (as previous iMacs may have been), so it may be easier to damage (scratch) the screen surface if care isn't taken.
Always use a soft microfiber cloth (preferably with no sewed cloth edges - find a seamless edge microfiber cloth), to clean the new iMac screens.
If you need to, this "auto" microfiber cloth is one of the best:
They are a hard to find style and are "no seam edgeless" style ... meaning they don't have a threaded sewed edge. Often many cheap microfiber cloths are made using a polyester sewing thread around tghe four outer edges, and even though the microfiber cloth itself may not scratch .... the four sided sewed edges can really scratch badly without knowing it.
Here is another hard to find "micro" Micro Fiber cloth tah is great to clean screens with:
WITH AN "AUTO/CAR" MICROFIBER CLOTH .... JUST DON"T USE IT ON YOUR iMAC, AND THEN GO CLEAN YOUR CAR WITH TH SAME CLOTH !
Since my previous stated link is now dead ...
Here's an updated google search for the "Mothers Ultra-Soft Microfiber Polishing cloth (16"x16")":
Also, a great tip I tried .... mix a small solution of 1/2 and 1/2 of White Distilled Vinegar with Distilled water, put it in a small CLEAN mist spray bottle ... and use a micro fiber cloth (lightly sprayed with the mixed solution), to really clean the new 2013 iMac screens, and a dry micro-fiber cloth to dry the screen. It really cleans off all the smug streaks!
That Mothers polishing cloth is terrible. It leave lint like crazy.
This is what I would recommend, provided you can find one. I bought a number of these in France.
Might be this.