I would be concerned that peanut butter or oil would stain the leather.
I heard several remedies for getting gum out of hair, but not out of leather.
My daughter's long hair flew into her open mouth the other day and took a large wad of gum out of her mouth. It ended up in her hair. Instead of using a remover (i.e. peanut butter), I drove straight to the salon and had her hair cut up to her shoulders. I didn't want to mess with what it would take to get the gum out of her hair! She loves her new haircut.