Need help BCCing entire Outlook autofill contact list

Today is my last day at work and my boss wants me to BCC anyone I have ever sent an email to announce my departure.

I have tried exporting all my sent messages and trimming the list by advanced sorting out the duplicate email addresses in excel, but messages with multiple recipients are plentiful and need to have the emails separated into individual cells at the very least.

I also tried the .NK2 file route. I downloaded the MFCMAPI program to find my hidden autofill contact file, but it can only be exported as an .xml or .msg file and I don't know how to handle those files properly to get the data I need.

Does anyone here have a solution to automatically add every autofill contact on Outlook as BCC recipients for a final email?

EDIT: I found a solution that worked for both of us. I emailed the clients I remember as the most important and set up an automated reply to handle those I forgot to message.