Is it possible to remove a page from Google index?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Justin Y: I think what you`re looking for is this:
  1. Block the page via robot.txt
  2. Use noindex 
  3. Return a 410 error response
  
  Even after doing this it will probably take time for Google to re-crawl the site to find out that page is gone and no longer exist and then remove it from their index.
• 
  Alistair Lattimore: The breakdown on this is as follows:
  
  robots.txt
  
  Blocking a URL via robots.txt stops Google crawling a URL, it doesn`t stop them indexing it. If a page has already been indexed, blocking it via robots.txt will stop Google crawling it in the future but won`t remove the URL from the index - at least not for an unspecified long period of time and if it is deemed an important URL (linked to frequently by third parties, it may never be removed). An example of how this manifests itself, you`ll regularly see references in Google search results stating that Google can`t display a description because the page is blocked via robots.txt.
  
  HTTP error codes (404/410/500/..)
  
  Once Google knows a particular URL produces an error, they will remove the URL from the index and the URL won`t display it in the search results. The obvious requirement for this to happen, Google needs to be able to crawl the URL to determine that it responds with a HTTP error response code - so the URLs cannot be blocked via robots.txt.
  
  Google Webmaster Tools URL Removal Request
  
  Using the URL removal request removes a URL from the search results but does not remove the object from the index. URL removal requests expire in 90 days, so if you haven`t taken more permanent action - it is likely the URL will re-appear within the search results after the 90 day time frame lapses.
  
  meta noindex
  
  The sure fire way to remove a URL from the index, so it will never be returned by Google under any circumstances, regardless of how popular the URL is -- apply a meta robots noindex tag or respond with an X-Robots-Tag: noindex HTTP response header for that particular URL