Stuff like "iKlear" is overpriced bulldung that is pretty much the branded version of what I noted here. If you buy branded stuff you should get a lesson in cash management. Just because Apple sells it doesn't make it magical.
On occasion, very, very, very diluted Windex - and never, ever, EVER, applied to a matte-finish screen.
Matte-finish screens get cleaned with a damp, lint-free cloth, usually spot-wet and applied to specific areas on the screen, always using a light circular motion. No need to wipe dry. No Windex or chemicals of any kind are applied to matte-finish screens.
I clean them with one of my cats. Cat fur must be one of the softest materials around, and they love the warm surface of the devices. Forget stupid iClean etc products, treat your Apples with some good natural cat fur. It just works.
I haven't seen that occur in 15 years. Of course, I am not cleaning my screen daily either. I make it a point not to touch the screen so I clean mine around twice a year.
That said, if you have a glass surface, it won't cause any damage.