Removing old Work Item Type from TFS 2010 Team Project

To remove an old work item type (WIT) from TFS 2010 Team Project

1. Open Visual Studio Command Prompt under Microsoft Visual Studio 2010 -> Visual Studio Tools
2. Make sure that you have admin permissions, and run

witadmin destroywitd /collection:<url of the collection> /p:<team project name> /n:<work item type>

*joychua97