At Best buy they have simple spray bottle cleaners specially formulated to clean LCD screens thoroughly yet gently and safely. I have a bottle made by monster the same company as the monster that makes all the cables.
The best way to clean LCD screens is buying one of the specially formulated LCD spray bottle cleaners and then using a very soft micro fiber cloth to wipe it down after spraying the cleaning solution. Water can work as well but the spray just dissolves the dirt on contact so you barely have to rub hard with the cloth to get it clean vs water where some types of crud take more elbow grease to get it cleared.
Also not all LCD screens are covered with a layer of glass. Many have the plastic matte type screen directly exposed with no glass covering it. Using glass cleaner on plastic is a no no. That's why you should buy a product designed for LCD's if you want to be totally safe.