Smudge on alum macbook cant get rid of. Under the glass?

I saw a smudge on my screen and tried to remove it with a tissue, but it didnt come off. It looks like it is under the glass...
It disappears when the screen is off so it must be the screen and not the glass.

Anyone seen this happen?
Will the apple store let me exchange it?

I have had 5 MBPs because of screen issues (2x dead pixels, 2x dirt under the glass and one good machine).

Take it back to apple and get a new one. They will try and tell you its not a defect but it is a defect in the manufacturing process that means you can get a new machine if you bought it with the last couple of weeks.

Went to the apple store with it and said they couldnt do anything about it and i had to ship it to the repair people because the macbook was bought online and they can only replace ones in the store.
is this right?

The Apple Stores seem to be very inconsistent when it comes to repairs, replacements and service. If there is another in your area, I would give them a try. It would be good to call Customer Service and see if they can ship one and let you transfer your files then ship the old machine back to them. I certainly would not use a tissue in fear of leaving marks but would get iKlear to clean it like the Apple Store cleans their displays.