Olive wood is a real bear especially is it's near fresh, the oil makes it a bugger to finish, a thorough wipe down with Acetone or Denatured Alcohol helps, then keep wiping down with DNA after each coat, left on it's own after a good sanding, the wood will take on a beautiful patina, I had to replace a refill on one
I made a year ago that had no finish other than sanding and burnishing with a paper bag, and it's looking great.
I'ts part of a set and doesn't leave the mans office but it does get used quite a bit, the natural oils of the wood seem to repel most nasty stuff.