My copy of Metropolis (The Kino Restored Authorized Edition) has a scratch in the disk material itself. Super Mario Bros. - The Wicked Star Story "Ah, the proverbial sad sack with a wasted wish."
How on earth can you get a scratch on the actual data layer? It is sandwiched between the two outer layers. If it is a normal scratch you can take it to a DVD rental store that has a disc resurfacing machine and they will usually put your disc through it for a nominal fee.