Not necessarily. If a disc receives too many scratches or serious scratches, you can't just buff it out good as new, because you can't repair damaged information and code on the disc. As for my answer, well before my answer, what were you doing to your friend's copy of Halo 3? Now to my answer, just tell your friend that you need time to save up some money to replace his game. If he doesn't like that, tough crap; that's how the world works. Besides, Halo 3 is actually pretty old and boring nowadays and he shouldn't take it as if you murdered someone.