How can I remove email attachments from sent email messages in CRM

How can I remove email attachments from sent email messages in CRM

I sent a few mail message with a 2.5 mb attachment.   

I don't need to retain the attachments would like to free up this room in my 'storage'.  This way I will have the email thread without the attachment.  Could not a way with right click context menus or in searching the forums.   

Any ideas on how I can remove the attachments but keep the messages?

Gary