ITunes Junk: iTunes is lot more than a typical music management app. CleanMyMac automatically does that for you. Sure, you can manually clean them out individually, but it would take hours to browse through your mailbox searching for attachments and deleting them. But once they are downloaded (using the Mail app), they get saved on your Mac and remain there occupying precious disk space.
Mail Attachments: Attachments in emails are often downloaded for one time use.
