(Optional) Export your site's comments.
At the Disqus admin > Settings > Advanced page, near the bottom, click the 'Delete site and comments' button. If you own more than one site, make sure you're deleting the appropriate site.
Remove the appropriate Disqus widget, plugin, or universal code from your site.
Important:
Deleting a site also deletes all its comments.
We cannot un-delete your site.