How do I manually Empty Deleted Items in Outlook?

1. Open Outlook
2. Right mouse click Deleted Items
3. Click Empty Folder
   
   
4. Click Yes on confirmation pop-up
   
   NOTE: Even though the pop-up says the emails will permanently be deleted you still have the 30 day grace period to Recover Deleted Items.
   

NOTE: Your mailbox size has now been reduced, but will take a little time to reflect this and remove any restrictions.