MainWP Maintenance Extension allows you to:
- Delete post revisions
- Delete auto draft posts
- Delete trash posts
- Delete spam comments
- Delete pending comments
- Delete trash comments
- Delete tags with 0 posts associated
- Delete categories with 0 posts associated
- Optimize database tables
To do that go to: MainWP > Extensions > MainWP Maintenance Extension and on the RUN NOW tab select your maintenance options, wanted child sites, after that click the Perform Maintenance button: