Expiry of news itemsBrowser Info Environment
there are two possibilities:
1. You can restrict the shown entries in a feed by the age of an entry. You can set that only entries are displayed which are, lets say, younger than 90 days. This is the prefered way.
2. A feed is only showing entries to which the user has the viewing rights. Therefore you can schedule the guest access or set the viewing permissions for the entry and set the permissions to expire at a certain date.