I recently had a hack that added several thousand bogus pages to my site.
I submitted a corrected sitemap to the Google Search Console (previously called Webmaster Tools) and turned all the links to 410, but Google still had most of them indexed.
I used WebMaster Tools - Bulk URL removal Chrome Extension to automatically submit the urls for removal. It is basically a script that takes a list of the URLs then submits them for you, one at a time. It will take hours to submit them all, but at least you won't have to do it yourself. Here's an article on how to use it.
You can get a list of the URLs that google is indexing by downloading the data directly from the Search Console. Go to Status > Index Coverage and select the valid results then scroll down. You will see that Google has indexed a ton of URLs that are not in your sitemap. You can download the first 1000 results. There's apparently a roundabout way to get all of them, not just the first thousand, but it involves API calls from excel. I just waited a few days between each thousand, as they slowly fell out of the index.
Another route is to have a WP plugin create a sitemap, then filter out the PDFs or whatever you are targeting. You'll probably have to do a bit of manual copy/paste/delete here. Just to be safe, I slowly scrolled through my list of about 2,700 spam URLs and deleted the legitimate URLs. It only took about 20 minutes.
If you aren't trying to permanently nuke something, like spam, and instead are trying to obfuscate premium resources, you should use other methods to prevent indexing those resources, such as a robots file. But if it turns out Google didn't listen or you dropped the ball, at least now you can fix the issue and get them removed from the index in only a few days.
In my particular circumstance, I'm wondering why Google doesn't have a time machine button, or undo, or reset. The idea is that I can tell Google the site was hacked a few days ago, but we've repaired it, therefore undo the last x number of days of crawling and indexing. But that would be too easy.