How to remove stain from glass

[ParagJain]

I had a screen guard on my iphone 5S for about a year, I removed it as it had gone dull and scratchy; Now this guard has left stains near the ear piece (sensor) and facetime camera.

Actually, these to portions of the front glass was always left exposed due to cut-outs.

There is a very distinguishable stain; I clean it up and it appears again.
Any way I can clean this permanently ?

thanks

 

[wxman2003]

Most likely the screen that was covered with the protector probably still has the oleophobic coating, while the portion that has been exposed for the past year has lost the coating. Probably nothing you can do.

 

[ParagJain]

Most likely the screen that was covered with the protector probably still has the oleophobic coating, while the portion that has been exposed for the past year has lost the coating. Probably nothing you can do.

oh dear, you could be right..didn't think about it and this kinds sucks !!