The old way to remove pages from Google's index without using 404s or a robots.txt file was to use a page at http://services.google.com:8882/urlconsole/controller. It now appears that if you go to that URL, you are redirected to login to Google Webmaster Tools.
The page reads:
Sign in with your Google Account to submit a removal request.
Use the Webpage removal request tool to request that information be removed from Google Web Search and Image Search results. You can use this tool to request the following types of removals:
* Remove outdated or missing webpages. * Remove information or images. * Report inappropriate content appearing in SafeSearch filtered results.
We'll investigate and provide an update on the status of your request as soon as possible. Removals that are processed through this tool are excluded from Google search results for six months.
If you're a webmaster and would like to remove your site's content from our index, get started with our webmaster URL removal tool in webmaster tools.
If you login, you can then remove three types of content, they include:
- Information or image that appears in the Google search results.
- Outdated or "dead" link in the Google search results that returns a 404 not found error.
- Inappropriate webpage or image that appears in our SafeSearch filtered results.
The removal request form is a lot more detailed and asks you a lot more questions than the previous form. Plus you are encouraged to login, if you would like to remove a page or search result.
Some are upset that there is no easy way to remove a page that has a 301 redirect from the Google search results.
Forum discussion at WebmasterWorld.