If you are talking about junk mail, you can set up Junk controls and train Thunderbird to recognise junk and sent it to 'Junk' folder or if imap account, the subscribed 'Spam' folder. https://support.mozilla.org/en-US/kb/thunderbird-and-junk-spam-messages Then at least you can catch anything that should not have gone into that folder. You can set the folder up to auto empty after X days or manually empty as and when you like. If you set it up to go to Trash then you can set up Trash to empty when you exit Thunderbird, but be aware that some server auto empty trash periodically. If it is a specific email address you do not want then you could set up a Message Filter, so that FROM contains email address, then delete.