The barbarian stomps off to the palace and demands an appointment with the exchequer. Upon hearing that the money is fresh from a dungeon, the official asks where the barbarian is staying and who else was travelling with the warrior. Then the official discreetly orders a small army of guards to go to the barbarian's inn, seize all money and goods and to arrest the barbarian's friends. Then he also places the barbarian under arrest. You see, the barbarian and his friends broke a number of laws concerning bringing loot into the city.
Ancient loot can carry strange diseases, curses and plagues.
The original owners of the loot may try to get it back. Next time you want to create an encounter that involves roleplaying, tension and conflict, think bureaucracy. If you want to slow things down, buy time to think and plan, or just limit the PCs in some way, bureaucracy is the perfect tool. Use laws, procedures, paperwork and delays between each step to accomplish what you need. This technique is best used if the PCs' are already somewhat aware of what they are up against ahead of time.