Do you mean saliva or Salvia? One is spit, the other is an herb. He he he.... you said it smells like dried spit.
If it smells acrid, it's probably a chemical in the tanning process. If it came from "over there" it may be have been tanned with who knows what. Some cultures even tan with urine.
But to try to solve your problem, before waxing, I would wrap the necklace in permeable tissue like toilet paper and bury the entire thing in activated charcoal which you can get from fish tank supply stores. Keep it buried for about a week, then check for odors.
It may, however, be a lost cause. I had a silk outfit that when warmed by body heat would give the most awful rotting fish smell. I washed that thing over and over in all kinds of solutions but was never able to get rid of that stink. It finally went in the trash.