Elmer's Glue works very well for repairing/restoring pistol boxes. I've been using it for years. I also use a little contact cement from time to time. Small, cheap, children's "artist" paint brushes are good for applying the Elmer's. I used to get them at the Michael's craft store, but had to order my last batch direct from the manufacurer. Some other things that are handy in repairs are small plastic clamps, a strap type picture frame jig, small scissors, tweezers and rubber bands. It's not difficult to do some pretty good repairs. "Restoration", however, is more difficult. The main problem is the lack of paper that closely resembles the original. I've been searching for years for a good match for the paper that Colt used in their pre-war boxes and have never found anything close. The best I have been able to do is to use small pieces removed from a really beat-up un-repairable box that is similar to the one I am trying to repair.
It's good be be patient when doing box repair. Do a little work and let the glue set up overnight and then do a little more. Trying to do too much at once will usually result in having to do it all over again.
Good luck and have fun with it!
- - Buckspen