Obviously not news to anyone here, but in case he's reading these comments - there's no need to go through and manually decide which of your emails you want to

Obviously not news to anyone here, but in case he's reading these comments - there's no need to go through and manually decide which of your emails you want to keep. Just download a copy of Thunderbird, or another free email client, then download all your email using POP or IMAP. Once you get a new email address set up, you can even upload all the old emails to it to make them searchable with your new ones if you want, using IMAP.