I keep running into URLs that no longer exist, but which Google Search still returns and end up giving me a 404 error. I know it'll get re-scanned eventually, but how do I prompt Google to re-scan it sooner?
You can request removal of a single search result by using the "Remove outdated content" tool.
- This request works only for pages/images that have already been modified, or removed from the web.
- If you need to remove personal information or content with legal issues, you should submit this request instead.
- Enter the URL copied from Google Search Results.
- If successful, cached result and snippet will be removed from Google Search results.
- If unsuccessful, learn why.
They don't mention how long it will take, but it certainly should be shorter than waiting for Googlebot to come around again.
More details about the Remove outdated content tool from Google Support.