You should not be using circular motions, especially on an anti-glare filter. You risk both scratching the screen or rubbing it to a haze.
the above is not true.
there is no risk of scratching the screen or rubbing it to a haze.
if u are using a microfiber cloth as i mentioned b4, unless u are putting extreme force, there's no risk of scratching the screen or rubbing it to a haze (not even sure what the last one even means...).
as an apple laptop user for over 15 years and having owned both antiglare and glossy, what getz76 has described has not happened to me... he might have used extreme force when cleaning his screen which is not suggested.
also read this Apple Support Forum:
https://discussions.apple.com/thread/2720501?start=0&tstart=0