I have recently updated a site that has existed for a few years before and was indexed by Google. The site structure has changed, some pages moved around, some should be removed completely as they are outdated. Some of those pages have PR2, some have PR1, some have PR0. I understand I lose nothing in Google's eyes if I remove a PR0 page, but what is the best way to go about the pages with better PR? I have a custom 404 page that links users coming though old links to the new pages on the site but I understand 404 is still 404 for bots. Should I just replace those old pages with some pages that look like my custom 404 page or add a note to those pages saying they are outdated and more recent information can be found on other pages of the site with a link to it?