Q0715 - Exim/exim GitHub Wiki
How can I get Exim to remove attachments from messages?
Exim does not contain facilities for modifying messages. You must use an external program if you want to do this. You can route messages that have a Content-type: header line via a pipe to a command that does the job and then re-submits the message to Exim. Alternatively, you could use a transport filter to do this job.