... The Dust InfraRed ToolBox (DIRT - a part of the Web Infrared ToolShed, or WITS, located at http://dustem.astro.umd.edu ) is a Java applet for modeling astrophysical processes in circumstellar shells around young and evolved stars. ... DIRT uses results from a number of numerical models of astrophysical processes, and has an AWT based user interface. ... Before refactoring, model data was represented within the user interface using Database and Record objects. ...