Selling to strangers was a significant occupational hazard for retailers in late Georgian Britain, one that was hard to avoid. The dangers were especially great in larger towns and cities, where shopkeepers were dependent on a steady stream of passing trade composed of a large number of customers that they did not know. Though traders risked financial loss and even possible prosecution by accepting counterfeit banknotes, refusal to accept them meant losing vital custom. In areas of growing urban populations, tradesmen and women thus faced an increasingly tricky dilemma in their day-to-day business as they dealt with more strangers whose trustworthiness and personal credit were extremely hard to gauge, at a time when banknote forgery was on the rise. The decisions that retailers made about both banknotes and the individuals who presented them for payment illustrate some of the ways that town dwellers sought to navigate the rising anonymity of urban society in the late eighteenth and early nineteenth centuries. This article suggests that traders relied on a series of techniques that in previous experience usually worked: Examining banknotes and those strangers who presented them with care, relying on the expertise of neighbors and members of their household, and dealing by preference with individuals who appeared to be linked to their local community. These behaviors demonstrate that modernity might have affected the lives and outlooks of ordinary Londoners in unexpected and contradictory ways, some strongly linked to older forms of society.