Hi, I hope you can help me on that matter. I have removed some pages on my site. Those pages were previously indexed by Google. After removing those pages I resubmitted a new sitemap with all new links from my site, but removed pages continue to appear as indexed error on webmasters tools. Do I have to use Site configuration -> Crawler access -> remove URL to remove those URL shown in the crawling error section, one by one, or will they be removed automatically after a certain time? Thank you.
I would suggest redirecting the links somewhere. The links to those pages still exist on the web so a 301 redirect will help Google figure out that the page does not exist anymore.
As Jon said if you have external links to those pages, it would be better that you do a 301 redirection of these pages. This way not only you can move their value to new pages but also will tell Google that the pages have been moved to new locations. Gradually these urls will disappear from Google. Otherwise you can remove these urls from Google indexing by requesting Google through webmaster tools that you already know.