Quickest way to level up gold hoarder?

What are some of the quickest ways to level up gold hoarder? Im not too fussed about what gives the most amount of gold since i have plenty of that, but i want the level 100 gold hoarder costume. Im currently in the low 80’s atm and was wondering what are some of the best ways to rep up quickly? Im not bothered if its an exploit or not i just wanna level up decently fast