Block it in robots.txt indeed to prevent it getting reindexed after you use the URL removal tool in Google webmasters.

The URL removal tool suppors the option to deindex (sub) folders, there's an option for that.

Thanks - out of curiosity, would it be best to just remove the site and start from scratch again? I just saw an option that would remove everything.

I am only asking this because the page titles being used in the SERP are wrong. I have made changes and checked the source HTML code to see that the <title> </title> tags are set correctly.

Google reports that the page has been indexed. And - the site title is ~still wrong~. For example, I have an old site title of : Login To The SiteCompany Name A

This was because I had 2 Wordpress plugins activated at one time: SEO Yoast and another (can't remember the name) - I had forgotten I had added it.

I deactivated one and then the titles started showing up correctly - i.e.
Login To The Site - Company Name A

But again, Google does not recognize this change. I have been submitting sitemaps and Google reports the pages have been indexed.

That was the reason for perhaps considering the "scorched earth" policy was to erase everything and try again - since Google refuses to recognize the changes.

Thanks but my understanding is that this is more of a preventative measure than a corrective one. It will work for any crawling in the future but does not address the wrong pages being indexed by Google in the present.

Yes, robots.txt should affect on google index in mater of days.

One of the way is to stop indexing is to have this meta tag -
<meta name="robots" content="noindex">

but you need it on every page.

Better go for webmaster tool and remove all url and also edit the robot.txt

more information can be found here
https://support.google.com/webmaster...r/156449?hl=en

Thanks for all of the hints and help!