Many thanks for the tip on WPS from Mike Middleton.
Here is another program tying me to Windows: Nero DiscSpeed.
In my old age, I have decided to sell off all my books and CDs. Before I send a CD out, I test it for playability. Nero has a superb program that scans the surfaces of all optical media and provides results in terms of readable sectors. It allows me to identify the track number and, by implication, the physical location of the problem. I have been able to find and clean nearly invisible smudges this way.
I have searched widely, and have only found one program that only works on DVDs. The results are also nowhere near as useful as Nero’s.