Rather than distroy your disks with software modifying them, why not try a physical solution first. It may just be dust on the disk surface.
Look here:
http://www.caps-project.org/articles.php?id=spinandblowThis has proven about 50-60% effective and has been tried with 100's of disks.
You can even go as far as using some alcohol and cleaning the disk surface with a cotton bud. Of course, you need to be very careful with this.
Use X-Copy's "verify" tool to see if you disk works again yet. Or, if the disk is not AmigaDOS format, like games, your only option if to try booting/playing them. Or, if they are original games and not been preserved by CAPS yet, you might want to contact them, and they will tell you.
If many of your disks appear damaged, it may be that your drive heads need a clean.
Note: Do any of the above at your own risk. It is unlikely you will make the disk any worse by the above (as long as you are careful), but you should make a backup of the disks first just in case.
