Your lucky. I use those Whitman type two row boxes that are about a foot long. I've got 9 of them full of 2x2's. What I've done is place one 2x2 inbetween different denominations with a little sticky thing sticking up. You know those pads of paper called Post-it's. They come in many different colors too. This way I can put the cover back on and they simply bend over. Also, since I've got a really bad memory, I use different colored ones and still write what is what on the part that sticks up. Index cards are OK if you don't use the covers but I keep all mine in those boxes covered so the littel tabs stick up and then just bend over when closed. Since I have so many of these boxes I also put the post-it's on the top of the cover to note what is in each box.