To mend the worn edges of tuck boxes use a felt tip pen to cover the worn part then seal the worn part with egg white. Egg white is a fast drying sticky substance, dries to completely clear, not yellows within time and not harmful for inks used on boxes. Egg white is also used to seal the leather.
Clear tapes generally yellows within time and also loosen. Scotch mylar like tape is most suitable kind but can be used in large patches. PVA adhesive can be used to mend but it dulls the surface and most PVA adhesives dries to whitish color.
Egg white is also used to give a shine to handmade paper when mixed with fine talcum powder but this is a different matter.