How do you clean a big screen TV screen?

My brother found a inexpensive big screen television for my parents, but it seems that the guy that had it, his grandkid attacked the front with a crayon. Does anyone know how to clean a big screen television? This is about a 54 inch Sony and has a filmy deal on the front of the screen that has vertical grooves in it. I would really appreciate any advice I could get, here or in e-mail, on how to clean that screen. Thanks!