The persecution of churches and religious groups under communism is well documented and the various secret police archives from the period have been utilized by researchers in order to trace the history of repression and collaboration and to understand the methods employed by totalitarian regimes to control their populations. The significance of these archives for the study of material religion, however, has been largely overlooked by scholars. The Secret Police archives in Romania and Moldova constitute a hidden repository of confiscated religious art, materials and publications that in many cases survive nowhere else, presenting an exceptionally rich resource for the study of religions in the 20th century. I argue that these archives represent an important resource for understanding not only how religious groups were able to deploy various creative art and media, resisting and critiquing the totalitarian and authoritarian system of the time, but also for exploring questions of ‘otherness’ and societal prejudice in post-socialist societies. Due to the controversial nature of the archives they present certain challenges in terms of methodology and ethical practice. In this lecture I will outline a new approach to the holdings of secret police archives that takes into account issues of cultural patrimony and the right of communities to access their sacred materials.