The “collapse” of state communism in Poland (as elsewhere in Eastern Europe) has ignited contentious questions about historical truth and memory and widespread accusations of “collaboration” with the former secret service. As part of the “transition” to a law-governed (Rechstaat), secular, capitalist democracy, Poland has employed the legal procedure called “lustration”, the exposing and banning of communist “collaborators” from public life. Lustration (lustracja) derives from the Latin lustratio, “purification by sacrifice.” Today it mainly refers to an ideological-moral examination of the political class and state employees by the public prosecutor. Yet, the social life of lustration expands well beyond its formal legal-institutional space, marked by informal accusations and rumors of betrayal and media revelations of secrets from the largely destroyed and highly inaccessible security archives. These accusations have implicated many public figures (e.g., legendary worker activists, priests, and dissident intellectuals), often provoking heated emotions and irresolvable suspicions about personal responsibility and public morality, as well as the possibility of producing truth on the basis of compromised security archives and witness testimonies of former security officers. By focusing on a few cases of accusation and court proceedings involving clergy and social activists, this paper will engage with the broader sociopolitical and epistemological conditions of truth-making and memory after 1989.