Contacts that have unsubscribed or hard-bounced will automatically be placed on the suppression list. This means that they will not be included in future sent projects. The contact will still be present in the contact list if you export (download) the list however.
If you wish to remove contacts from your list that are not sendable, you can do this by using the Search/Segment option in the List Manager.
1. Select the list that you wish to search or leave default to search all lists.
2. From the "Advanced Column" drop down list select "email_sendable". Enter a zero "0" in the value box. Click "Add". (Note: For Unsubscribes only select email_unsubscribe and enter a value of 1. For Hard-bounces only select email_hard_bounce and enter a value of 1.)
3. In the drop down box under "What do we do with the results" select Delete from a list.
4. Select the list you wish to remove the contacts from.
5. Click "Go"