Build a 100% anonymous messaging app you can self-host. The server is ready; for access details or help running it, see Need the server?.
from mailbox import MailBox mailbox = MailBox('imap.gmail.com', username='username', password='password', ssl=True) # Gets all messages all_messages = mailbox ...
(RFC3501 has a great deal of information if you're open to experimenting!) Time and again I've used the reference section on SEARCH commands and that familiarity paid off for my "mailbox sweeper" ...