A guy who knows a lot about recording told me.... If your source is vinyl and has dust-crackles, then run the stylus in isopropyl alcohol, sometimes called isopropylene. Sit there with an artists paintbrush and keep that bit of the record wet. It cleans up the sound, and even cleans the record.
I've never tried it for CD recording, but it works well for -to tape, so it should save some time.