How do I decode a base 64 encoded 'attachment' that is embedded in a mail message?

If you receive an e-mail with an attachment embedded within:

  1. save the e-mail as a plain text file
  2. edit the e-mail and remove any headers
  3. Delete everything before and including the lines that look like:

    Content-Disposition: attachment; filename='13234.pdf' ^M

    Delete everything including and after the lines that look like:

    ------------- End Forwarded Message -------------^M

  4. At a terminal line, type:
mimencode -u name_of_text_file -o new_file