On the My Moovs page, just click the trash can on the thumbnail of the Moov you want to archive. It will be highlighted:
You will then be asked if you’re sure you want to archive the Moov. If you are sure, click Archive:
The Moov will then be moved to the 'Archived' section.
Note: It is not yet possible to permanently delete a Moov.
If you change your mind, you can Unarchive the Moov by clicking 'Archived':
Next, select the Moov you want to Unarchive, then select 'Unarchive' from underneath the video player:
Your Moov will then be moved back into your 'My Moovs' section.