Since there's no value-add for these pages, I would probably request removal via WMT. That's the quickest and easiest way to get rid of so many zero-value pages. When you simply return 404 or 410, as I have been doing, Google will continue to try to crawl them, and they will sit in the index for quite some time. I noticed a large portion of deleted pages disappeared right before the last Panda update, but there are still about a dozen left, even though I have been returning 410 Gone for a month and a half now. I was scared to remove them via WMT as I feared I might lose some (historical) value, somewhere, somehow, I don't know. I doubt that applies to your pages.