You could use this:
<META HTTP-EQUIV=”PRAGMA” CONTENT=”NO-CACHE”>
It instructs the browser not to cache the page. Also you may use <META HTTP-EQUIV=”REFRESH” CONTENT=”1;URL=http://www.yoururl.com”>
this forces the page to refresh after 1 second, which is annoying an I think can have a detrimental effect on search engine spiders.
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