[gregjor]

Delete the documents and let the sender know they shouldn't send stuff like that by email.

As for "deal with," I don't know what kind of answer you expect. You can only do so much to protect people from themselves. How to deal with people who can't drive a car safely? Who can't do their job? Who can't organize a meeting to not waste everyone's time? Sometimes you avoid them, sometimes you try to help, sometimes you just have to endure and remind yourself you can't control or change everyone's behavior.