Just use a soft clean duster to remove any dust that accumulates over a period of time. Very light pressure.
If you do get any finger marks or other splodge on the screen, use a clean lint-free soft cloth dipped in a mild solution of soapy water and well wrung out. Wipe across the screen single light strokes and buff up with a clean soft dry cloth.
I've had my TFT for over 8 months now and only ever used a soft cloth to remove dust, but my sons laptop often needs a good clean to remove greasy marks and the above method works fine, leaves no streaks and no damage to the screen. j.