What to do with old index pages?

On our old forums (Pre-vbulletin, pre-VBSEO) we had a process that created a bunch of plain HTML index pages for Google to crawl. These were hiden from normal browsers by JavaScript.

On our new forums with VBulletin and VBSEO, we're using VBSEO's Google Sitemap. But Google still has the old HTML index pages in it's cache and is still sending users to them. Any suggestions for what we should redirect those old index pages to now? They don't correlate exactly to any new existing pages in vBulletin. Thanks for any advice.

If there are no corresponding pages for them now then you can simply redirect all of them to the forums (or domain) root.