50% solution of isopropyl alcohol and water is probably what your manufacturer recommends. Do not use windex or any other ammonia based sprays unless it specifically says in your documentation.
I have found that the premoistened ones dry out and leave a lot of streaks. The best thing I have found is a glasses cloth (or any soft lint free cloth) and a bottle of cleaner solution (commercial or the 50/50 homemade mix I listed above) works best for me.
This
one works wonders, especially if you are using it on a laptop and want to have it with you all the time as it is very compact..