What happens with treasures after a king abdicates?
Do they stay in their kings and dukes villages untill they join another kingdom?
the treasures will stay in the village/villages where the treasury was active
if the village/villages is/are within the influence of a kingdom, the "new" king could collect the treasures as tributes (but if you don't allow the new king to collect the tributes, the treasures will stay there)
you can send spies to see them