How do I remove blog content from Google?

You … Don’t. You could Try asking those places to unlist you, but once you’re on the net, it’s there for a very long time.

https://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=164734

Google Webmaster tools ( https://www.google.com/webmasters ) will let you delist pages on your domain that are appearing with outdated results. (According to certain criteria)

If you add nocache / noindex / nofollow tags to the pages, Google will respect them and not index to begin with or if you add a robot.txt file to your website and ban the Google bot, that will also stop it from indexing new pages (don’t do both as the robot.txt will stop the Google bot from seeing the nocache / noindex / nofollow tags).

https://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=156449&from=40360&rd=1

Google is just weird that way imho. I’ve tried de-listing my old website for ages but it simply refused to disappear…