I had the same question. I just used some warm water and the silk cloth that came with my oakley glasses. I dipped the cloth in warm water, squeezed it almost dry and wiped. worked great, no chance of scatching and no chemicals used.
This is something that can be done to decrease the cleaning of the screen by a factor of 10. Okay, 10 is an arbitrary number, but it also makes a point. Get yourself a feather duster and dust the screen daily. It's the dust that settles on the screen that attracts moisture and the pollutants in the air that are then transfered to the screen as grime. Keeping the dust off keeps the grime off. Fifteen seconds of cleaning daily with the duster will save you several hours over a years time, and also the risk of damage to the screen by over cleaning. A dedicated duster is reccommended.