Does it sound furry in a CD player other than the computer's? If it is an old disc, a wash in soap and warm water might help. If it is a computer-only track not suited for playing on a CD player, you can clean the sound up digitally if the problem is int he file itself. There is one application called SoundSoap that does this for certain kinds of hum, crackle, and pop. Gneral bandpass filters can be applied with SoundStudio.

If the problem is with the physical medium and washing doesn't help, it may be tiny scratches in the CD surface. Dunno what to suggest for that.

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