This paper investigates whether a clean banknote circulation helps the general public to more easily detect counterfeits. We conducted an experimental study with 250 consumers and 261 cashiers in the Netherlands and Germany. Participants received 200 banknotes with either a high or a low average soil level. The banknote test sets contained 20 counterfeits to be detected by the participants. In the tests, candidates identified more counterfeits when sorting clean banknotes. However, the level of cleanliness itself did not appear to help participants in distinguishing between genuine and counterfeit notes. In fact, new and clean banknotes raised suspicion: they were more often declared as being counterfeits – correctly or not.