for crt NOTHING works better then this:
Get 2 paper towels, crumble 1 into a ball and hold it in running water for 5 seconds or so, then squeeze it to get the excess water out, then wipe off the moniter with small amount of force, this will get it really clean, then use the other paper towel to dry it, and your done.
Dont waste money on glass cleaner and such when water does the same thing, for crts anyway, dont know about lcds.