Permanently delete your mails on thunderbird

When you are deleting mails even when emptying the bin, they are not deleted. So thunderbird keeps these mails in a file.
Here we will learn how to permanently delete these mails or messages:

There are two solutions:

• Manually
To permanently delete your mails/messages, go to “File” then “Compress files”.
This will erase all messages in the folder or the selected account. This has to be done several times if you have multiple accounts.

So you can compress all the files at a time using CompactAllFolders (Extension)

• Automatically
It is also possible to configure Thunderbird to automatically compress all the files when it saves at least some space.
To do this, open the Tools menu> Options (or Edit> Preferences), then in the "Advanced" category, open the "Network and Disk Space."
Check the "Compact folders when it saves at least ... Kb" and fill in the field by the value of your choice (a short message is about a KB).