You can delete conversations from your Inbox when you no longer need them.
You can also delete individual messages from a conversation instead of deleting the entire thread.
In Global Navigation, click the Inbox link.
Select the conversation.
Click the Delete icon.
Note: You can only delete your copy of the conversation. You cannot delete the conversation for all recipients.
To delete multiple conversations, select the message checkbox or press the command key (Mac) or control key (Windows) while clicking each message you want to delete [1]. Then click the Delete icon [2].
Select the OK button. All messages from that conversation will be deleted.
Note: New messages sent to you by any participant in a deleted conversation will still appear in your Inbox.