In one simple step, you’re able to bulk delete student blogs using My Class.
Once a site is deleted no one is able to view the site or access the dashboard and any one visiting the site URL will see the following message:

Do NOT delete a blog to create a new username or fix an issue with a student username.
Do NOT delete a blog to get rid of old posts or content.
Contact Edublogs support if you need to change a username or remove old posts so we can assist.
Bulk delete student blogs
Student blogs attached to a class blog via My Class are deleted in My Class > Student blogs.

Select the student blogs you want to delete by clicking on the check-mark next to their site title (their site title header changes to blue when selected), select ‘Delete selected blogs‘ from the ‘Bulk actions’ drop-down menu and then click Apply.

This automatically deletes these blogs and removes them from your Student Blogs page.
Restore deleted student blog
Once a site has been deleted no one is able to create a new site with the same site URL.
Contact Edublogs Support if you’ve deleted a site by mistake and need us to bring the site back online.