I was deleting whole pages of posts when I got to page 5 and thought 'how many pages are there?'
If you see more, don't delete the pages, go after the user accounts. Go to one of their posts, hit the spam button on the bottom. This will bring the Spam Blocker feature up. Click the big blue button "CLEAN" and then it will check for other users with the same IP and list them with a "SPAM" button to their right. Click each one of those spam buttons and it will kill the posts AND account.
I was able to move through about 40-50 users in 5 minutes or so yesterday morning before I had to go to work with the feature.