The very fine abrasive plastic headlight lens cleaners/polishers available at auto supply stores work very well. I've used one recently called plastX on my tired old lenses as well as on a fair amount of old nitro-cellulose wrap. It worked very well on both. I even had a kit with wrap that was heavily inundated with lots of micro cracks and had lots of oxidation surrounding those cracks. It improved even that wrap to a point that I could sell the kit.
Scratch marks from sanding are unfortunate and a 100% no-no. They needn't happen but some of that damage can be taken away with PlastX( or equivalent). The deep scratches are almost impossible to remove but you can get a shine on the material surrounding those scores and they might not be so noticeable.
Wraps are very sensitive to solvents that dissolve them. A glue bond might look and feel great , as soon as done but 6 months later, the wrap could be discoloured or worse. Stick with water soluble contact cement for repairs of lifted wrap. That's what is used as an O.E.M. product , so follow suit and you won't be disappointed in the future.