This briefcase was mailed to me. I didn't know the age but I would suspect it was at least 50 years old. The challenge was to clean and recondition the leather without damaging it. The edges were frayed and very dry.
Here's a picture of the back, which was in better shape than the front.
As you can see when lifting the flap, the under part was protected from most of the damage.
Below is the restored briefcase.
This process took many hours. I cleaned it with a mild detergent, then treated it with leather conditioners.
Matching the color was very tricky. I blended the colors to best match the original.
After refinishing, I treated with a sealant, which will protect the briefcase from further stains.