Humanities researchers tend to work with data derived from heritage collections, such as museums, archives or heritage libraries. Ideally, these data remain available for anybody to use for their own research interests. Often, however, when the projects which generate the data have ended, there are no means to turn the datasets into truly interoperable and reusable resources. It is therefore fortunate that the CLARIAH digital infrastructure for the Arts and Humanities has now designated funding specifically for that: curating existing heritage data sets with the aim of making them useful for a wide range of scholars.