Between December 2012 and September 2013 the United Kingdom government oversaw one of the largest destructions of a collection of human-derived samples ever conducted. Approximately 7,753,000 DNA samples and 1,766,000 DNA computerized profiles associated with the UK's policing National DNA Database (NDNAD) were destroyed or deleted. This paper considers this moment of exceptional erasure and the consequent implementation of new processes for routinely discarding and keeping samples and their associated computer records. It is divided into two parts. The first discusses the rapid growth of the NDNAD; the changing legal, ethical and political landscape within which it was promoted and contested; and the developments that led to the decision to limit its scope. The second shifts focus to the operational challenge of implementing the destruction of samples and deletion of records. The NDNAD case allows us to examine the labour and continuing uncertainties involved in erasure of biological data and the emerging norms and practices associated with collecting DNA in differing formats. It also sheds new light on the importance, interconnection and ongoing instability of the ethical and practical biovalue of genetic collections: as the paper argues, far from ending the NDNAD, a more rigorous regime of erasure has helped, for the moment at least, to secure its future.