URL removal from Google index

How do I get old pages out of index

[onebaldguy]

Our site has pages created for certain products that are only available for a short period of time. Pages are created dynamically for each of the new products, but are no longer valid after a certain period of time.

The pages are getting in the index, but then are staying in the index for a long period of time - even though the page has no content and basically a blank page. How can I get these pages out of the index?

Should I give a 404, 410, 301, or simply put a no-index tag on the page after the product is no longer valid?