I clean it out twice a week. I never let it get to be enough that i feel im wasting something by not harvesting the oil. Not enough develops to make it worth your while imo. You can always take a small bud and slide it through the oiled stem then vape that bud.
I just run a twisted piece of a napkin through it and throw it away. I concentrate on saving all ABV for edibles. Much more worth it IMO