We can access this tool by clicking the Tools menu and clicking Mailbox Cleanup.

 

Here’s what it looks like:

 

 

You can see that there are lots of options in here for cleaning up Outlook.

-          View Mailbox Size: Gives you the overall size of your mailbox (if you’re using Microsoft Exchange Server), or your personal folder file (for everyone else). It also displays a list of the size of each folder.

-          Find: Do a search based on the date or size of items. This can help you organize or delete old or large messages. (When you click Find, an Advanced Find window will appear with your results.)

-          AutoArchive: Archives your data based on AutoArchive settings. (Default settings will be used if you haven’t specified any yet.)

-          Deleted Items Folder: Check the size of your deleted items folder, or empty it.

 

Once you’re done using the tools in this window, just click Close to go back to the main Outlook screen.