If you’ve ever gotten a ton of spam comments that went live and are mixed into your site’s good comments, cleaning them up can take time with the default WordPress settings. Here are a few tricks to make that go much faster.
To mass remove comments in WordPress, you just select the check box in the header and then select ‘delete’ or ‘mark as spam’ from the Bulk Actions drop down menu.
By default WordPress gives you 20 comments on a page. To increase the number of comments seen on the screen, simply click on the ‘Screen Options’ link at the top and update 20 to 100 or more.
Depending on your hosting, there may be limit. I was able to update mine to 150 per page which made removing comments go much faster. I wanted to do 500 per page, but when I clicked delete the host that blog was on errored out.
If you really want to go crazy, log into your web control panel and then into phpMyAdmin. Click on your database, then the wp_comments table in the sidebar. Click order by comment ID with the highest number on top. Then tell phpMyAdmin you want to show 2000 comments starting at record 0.
This is more advanced, but you can go so much faster as phpMyAdmin has fewer limits than WordPress.