Tony,
You may want to keep the printed Census material due to the fact that those reports aren't available online via the Census website. They are only available via FTP as I recall. Patrons do prefer the printed version.
If you must withdraw, retain those for your state and bordering states.
As for withdrawing titles, use the Superseded List as a guide. I don't know if it has been updated since I last volunteered for it, but, It will help you very well.
Also, remember to submit your list of withdrawals to the Regional and then state depositories before offering it nationally.
Carlos A Diaz
AskCarlos.com