not2easy - 9:08 pm on Aug 25, 2013 (gmt 0) [edited by: phranque at 9:27 pm (utc) on Aug 25, 2013]
Are you sure? My impression was that if you're removing an area, you can have it removed from cache and index right away, rather than wait for google to discover that it's gone.
I got the info from notes in a 2007 .txt file back in my GWT stuff, but I just went and looked it up again. Good thing, here is from the horse's mouth:
URL removal requests expire after 90 days, after which the content may appear in our search results again. To remove a page or image from the index completely, you must do one of the following:
Make sure the content is no longer live on the web. Requests for the page must return an HTTP 404 (not found) or 410 status code.
Block the content using a robots.txt file.
Block the content using a meta noindex tag.
To remove a directory and its contents, or your whole site, you must ensure that the pages you want to remove have been blocked from crawling using a robots.txt file. Returning a 404 isn't enough, because it's possible for a directory to return a 404 status code, but still serve out files underneath it. Using robots.txt to block a directory ensures that all of its children are disallowed as well. Note that disallowing crawling with the robots.txt may not always prevent the URL itself from appearing in our search results.
More information at the bent link above.
URL parameters can not de-index URLs.
[edit reason] fixed url [/edit]
[edited by: phranque at 9:27 pm (utc) on Aug 25, 2013]