You can clear the Search Engine index of the Content Server by clicking on a corresponding link at the Content Feeder admin page. The Content Feeder must be stopped using the stop link on the administration page before the collection can be cleared. When stopped, a link "Clear the Search Engine index" shows up on the Content Feeder admin page.

This will remove all content of the Content Server from the Search Engine index. All contents will be reindexed when the Content Feeder is restarted.

Alternatively, you can use the JMX operation clearCollection() of the Feeder MBean. See the reference of the Content Server Manual for a description of all available JMX attributes and operations.