I came across an article in wikiHow called “How to Fix a Scratched CD“:
While compact discs (CDs) are remarkably durable, itâ€™s nearly impossible to prevent scratches and scuffs from occurring from time to time. The resulting damage can be either a skip in your favorite Bob Marley track or, in the case of data CDs, the loss of that spreadsheet you worked on for two weeks. Donâ€™t despairâ€”repair! While commercial CD repair kits and CD refinishing machines are available, you may be able to repair the damage on your own with products you already have.