How long does it take for pages to drop out of Google?

Stupidly when I was setting up my site I neglected to create a robots.txt file and now my search results are polluted with lots of useless data. Does anyone know on average how long it takes pages to drop out of Google once you have created a robots.txt file disallowing access to those parts of your site?

There is no average. sometimes it happens in an hour, sometimes it happens in 7 months. it's entirely up to google.

you can try to speed up the process by submiting a url removal request in the google.com/webmasters area

Originally Posted by briansol

There is no average. sometimes it happens in an hour, sometimes it happens in 7 months. it's entirely up to google.

you can try to speed up the process by submiting a url removal request in the google.com/webmasters area

Thanks. I'm a bit concerned with the request for removal of a URL as I don't want any mistakes to happen and the rest of my site get removed as well.

I guess it is just a lesson learned. Always use robots.txt files if you don't want to pollute your search index.