Visualizations are a powerful way for people to explore and analyse data. Libraries, by their nature, have access to a generate substantial amounts of data. Even with the best of intentions library data can be messy. Whilst we can apply structural frameworks like cataloging rules, subject classifications and controlled vocabularies at some point the machine world is interfaced by humans. ‘Messy data’ was the challenge faced by Metaweb Technologies, Inc. who in 2007 announced the launch of Freebase (www.freebase.com), a community project designed to create “an open shared database of the world’s knowledge”. As part of this Metaweb created Gridworks, an open source desktop tool designed to help in cleaning messy data. Now called OpenRefine, we look at how this tool can be used to show how the history of repository deposits can be visualized as ‘code swarms’.