You can already remove attachments in Outlook—but only one at a time, which gets to be a big waste of time.
Outlook Attachment Remover (clever name, huh?) does just what it says, but in addition to removing attachments from one message at a time, you can scour an entire folder clean. This works well if you are on an Exchange server with a mailbox size limit, or you just want to put a bit of spring back in Outlook’s step.
Outlook Attachment Remover Frees Up Inbox Disk Space [Lifehacker]