Do not use Neetsfoot oil! Within your lifetime it will rot the thread holding the box together.
The British Museum Wax, Renaissance, is a better choice, or look for Pecard's leather treatment and give the leather a "light" coat. Pecard's is also sold by Redwing Shoe outlets as a waterproofing paste, comes in little tubs for under ten bucks.
Do not try to color the leather. The brown tone is a result of the tanning process, and is over 140 years in the making. Enjoy it as it is, the olde veteran deserves the best care, which in the case of leather, is often the least care. Do not over "goop" the leather. It is animal skin and bound to age.