Use anything BUT rolodex. Rolodex uses PVC plastic which has harmful long-term effects to anything it holds. This is well known among coin collectors who saw their coins destroyed over the years. I use Avery pages myself because the plastic is archival quality and they are cheap. My collection is huge and cost is a consideration. I can get 10 pages (which hold 10 cards each) for a little under $3. Once in a while they are considerably cheaper.