Whenever I try to play those maps, my 360 gives me a disk read error... Now I've tried cleaning my disk, but it's not working... Any suggestions on how to clean it?

buy a new one

That happened to a friend of mine who could never load Pipeline.
Either call and complain to Microsoft to get a new one or buy a new copy.

Look around / ask people whether they have any disk cleaning equipment, that could help.
If you live in the UK go to your local gamestation, a lot of the game station stores now have the real disk cleaning machines in. They charge you 2.50 for using it, but sometimes it does help.

same thing happened to me and crossfire. I got me one of them disc repair crank wheel thingys. Works fine now.

Thats happened to me but it was only vacant. I used a disk cleaner on my 360 and it hasnt scrattached anything since. I never really liked vacant so im not going to buy a new disk to get a map that im not bothered about.

All right will try that. I think it should be able to be salvaged because there are no major scratches on it, like what would happen if the 360 was moved while it was playing.

Does anyone know if Gamestop has any services like the UK gamestation has?