If you updated a really old page on your site like the terms of use (or any page that hasn't been updated for like 3 years) and you want all the SEs (most importantly Google) to recrawl it as quickly as possible to get all the latest information. How would you go about this?
There are tools that you can create multiple sitemaps for big sites. Here's few: http://www.xml-sitemaps.com/standalone-google-sitemap-generator.html http://www.freesitemapgenerator.com/news-archive.html#2005nov27 http://johannesmueller.com/gs/ http://www.sitemapxml.com/
to my own experience, when you updated the content on your page, google bot seems to come back a day or two to recrawl the page without resubmitting the sitemap
If your page is connected to the regular updating page then you need not to do anything, G crawler will automatically crawl it. Or in other words, if you want to re crawl your old pages, simply link to the regular updating pages.
Just popularize the page..make the required page visible to GoogleBot. Bookmark the page in any top social bookmarking site.(or you may even link it via dofollow blog comment)
you have a running site and page is old but you can just check how often your pages get crawled as last date when it was crawled it will take similar time if you do nothing. you can use social book marking of just edit your post above put your url in that post and it will be crawled.
link at it from a trusted blog, (G has to follow the link when the new blog posts pings and is indexed) delete and re-submit your sitemap, that will usually do it, if not, after that you just have to wait until the re-crawl is scheduled.
Create sitemap again if possible and resubmit it to Google. Also doing social bookmarking of page can make it to be recrawl again