When modules, pages, and tabs are deleted they remain indexed until purging occurs. Purging will also delete any duplicates that are indexed. To enable purging, make sure Enable Purging is checked in the Seamus settings.

Set Purge Every X Hours to an integer for the number of hours between purges.

If you plan on using Moderation, you will have items that are approved and unapproved for public display. When purging is run, it can also delete unapproved items that are older than a set amount of days. Set Delete Older Than X Days to an integer for the number of days an unapproved item will remain indexed before deletion.