aristotle - 11:42 pm on Aug 3, 2013 (gmt 0)
Yes it's possible that some of the pages on the old site aren't penalized, but I don't see how you can know for sure. And even if you safely transfer the traffic from those pages, there would still be other pages with traffic that can't be safely transferred.
Another approach, which will no doubt be criticized by some here, is to put an ordinary dofollow href link on each page of the old site with the anchor text "This site (or page) has been moved -- Click here to go to the new site (or page)".
Most visitors will click the link to go to the new site. And the links will also transfer most of the "pagerank juice" to the new site, but shouldn't transfer any of the penalty.