I think my Xbox 360 is scratching my COD 4 disc

The other day I tried to play a level on Cod 4 and it wouldn't let me. The xbox 360 came up with the error message that the disc was unreadable. I checked my COD 4 disc to discover a few circular scratches, not deep or anything, but noticable, and a lot of little scratches. Im always really carefull when handling the CD, and I haven't moved the xbox360 whilst it was on. So what the hell is going on? When I play Cod4 multiplayer I get a like a faint clicking noise coming from the xbox 360, I wonder if somehow the 360 is making contact with the CD. I have two other games and those discs are pretty good condition, but COD 4 looks terrible.

Im fairly annoyed, work endlessly for overpriced games $110.00 (au) only to have them rendered unplayable. Your thoughts? Suggestions? Possilbe causes? Any help would be appreciated

that happened to my first 360 i only had it 3 months at the time, took it back to the shop and they replaced my scratched games and faulty console.

its nothing to do with leaving your games in your console.