Unable Delete Meeting Invitations or their Attachments

We have more than a few User’s who have meeting invitations that they are unable to delete. These are old invites that have either been declined or are in the past. They do not show up in Views>All Documents. I created a new view that shows everything. I am unable to delete these emails or any attachments in them. I have Manager access to their mail files. I’ve also turned on Full Access Administration with no luck.

Any advice would be greatly appreciated!