[MlMt] Secure deletions of emails

[Rob Willett]

Hi,

I'm trying to securely delete mails and attachments sent to me. These 
are personal information, such as peoples home addresses. I've deleted 
them from the mail server but am trying to work out how to delete them 
as securely as possible on the Mac. I know the srm command for files on 
El Capitan but am trying to work out how to make sure I haven't left 
anything lying around in Mailmate.

I have searched but can't see anything beyond simply deleting the mail.

Any help or pointers welcomed.

Thanks

Rob