Visualization is a key step in scientific analysis and understanding in many fields. Scientific studies often require development of software that produces visualizations. However, as a study proceeds, the software evolves, and both developers and expert users have to periodically ascertain how code modifications affect visualization output and hence the results of the study. To our knowledge, no current visualization framework enables tracking and comparison of the lineage of scientific visualizations. We describe an approach for comparing and maintaining the code for scientific analysis and modeling through interactive comparison of visualization output. We have realized this approach in a tool called Mr. Clean. This tool provides a framework for combining different visualization tools, interaction devices, and display middleware for visual comparisons on highresolution displays. Mr. Clean also provides user-configurable interactions supported by many devices. We provide use cases and a requirement analysis for our approach, and we describe the design and implementation of Mr. Clean.