I collected all the CDs I had that were damaged in one way or another. They ranged from ones that would not play to ones that would get stuck on a particular track to scratches that impacted the sound. I had 13 that fit into this group. I followed the directions exactly as written. They say that you can repeat the process numerous times without damaging the disk. I did all of them one time. It states for deeper scratches that you can focus the repair on that area. I did not have any that required this treatment.
Results: I was very pleased, all 13 played perfectly after the repair process. I was not able to detect any degradation, however, I must say that many of these I have not listened to in a couple of years or more. I think she paid about $50 for it at Best Buy. If I were to replace the CDs that were damaged I have already recouped her investment.