If you have a strong smelling cup it may be a spring cut horn versus a fall cut horn in my experience they have different impacts flavor wise. Some say I'm nuts though.
Lining with pitch can help, but then you get the pitch flavor (pine) also what you get from Townsend is pitch not brewers pitch. Brewers pitch is black not yellow and stays soft. It is pitch mixed with sulfur which rather like vulcanizing rubber for a tire keeps it flexible. One thing to keep in mind is that horn is sort of the original teflon, pharmacists tools were made from it for ages since nothing sticks to it (at least not well) and you will get chipping and peeling of anything you put in (which is why the food grade epoxy folks are backing away).
As mentioned earlier, hot has more taste then cold beverages, and the longer you let it set the stronger it tastes. But you can let the cup stand with water in it and see if it gets an oily film on top you can try and soak it out. Dry corn masa (fine corn meal from a mexican grocery) can be used to pull residual oils out as well. (You use this to take grease paint out of leather and costumes in theater.
While I love beeswax for alot of things, I don't recommend it for drinking cups, it collects stuff, and melts onto stuff at the most annoying moments.
