How to clean up a shared Outlook mailbox that is almost full

For cleaning up inboxes, there are only 2 options:

Go through manually and choose what to delete (and what to save)
- You would need to log into the Web version of 365 and open the shared box in Outlook to be able to delete the emails
- You can sort each folder by Oldest first
- Emails would need to be manually highlighted (or shift click to highlight in bulk) and then Right click > Delete
- Once you have verified that the emails you deleted are not needed, you need to empty your trash to free up the space

Use a time-based deletion tool that does not have many parameters to choose what is saved
- This would also need to be done on the web version of Outlook which only allows you to keep emails within the last year
- You can select which folders to empty, but that’s about all the control you have
- Anything outside of a year back would be deleted and cannot be restored! You cannot undo this!
- This option can be accessed on the web by going to Settings > View All Outlook Settings > General > Storage > Empty > 12 months and older

Schreenshot image displaying the settings window for time-based deletion of emails.

Please consult with your supervisor which option works best for you, as option one will need to be used if you are required to save emails past 1 year.

Essentially this should be done on a regular basis so that they do not pile up.