First, blow the dust off the surface, using something like a vaccumm running in reverse, or a air pressure hose. Not that much air pressure should be required. Then get a small, soft brush with soft, but fine bristles. Softly brush the surface with this brush, gently massauging the suface with the bristles. Not much pressur here. You might want to wipe the surface, in conjunction with the use of the air hose, to blow the surface clean. then massauge the surfac, as I said, very gently. The trick is to pull as much material off of the surface of the screen without rubbing -any- of it into the screen's surface.
So, air, then air and wiping, then air and massauge. This should do the trick.