I had a blog site, i.e. http://example2.com, then I bought a new domain, i.e. http://example.com and 301 permanent redirected example2.com to example.com. But when I get into the Google Webmaster Tools, if I get some 404, and then click into the link and see the "Linked from" tab, it shows some links like:

• http://example.com/post-1
• http://example2.com/feed
• http://example2.com/post-1

According to Google, if you change your domain, just use a redirection for at least 4-6 months, but it almost passed. Then why Google has still traces of my old site?

The issue is important, because I don't want to pay for the old domain anymore.

I tried deleting my existing sitemap.xml and recreating it from the new site, but still such links are stored. What could I do?