This screencast goes through a simple (but overlooked) way of deleting a number of managed definitions using application designer rather than deleting them manually from the database. As managed definition in application designer is basically anything that you can insert into your project using the Insert > Definitions into Project from the menu or CTRL + F7. Examples of definitions you might have a need to delete include process definitions, job definitions, permission lists, roles, and URLs. In some cases there are other ways to do this in the system, so this is just one approach.
Deleting Managed Definitions