A. The safest method for cleaning your PDA screen is to treat the screen like a camera lens or a pair of glasses and use a micro-fiber cloth, which won't scratch the screen surface. Be aware that cotton is slightly abrasive and might scratch. Don't use compressed air because it contains super cold liquid that can exit the spray can and damage the screen. Even if you test the spray from the can so all the liquid appears to have been expelled, a slight tilt of the can will release more liquid.