This has bothered me for some time. On occassion, I've asked tellers if they had any older currency. The answer is almost always, "Yes, but it's packaged to be sent out." They've told me that they have to send it to be destroyed because it's either too damaged or "too old"(!)
I've offered to buy it but none of them would sell it to me once it was packaged (wrapped for transport). The only thing I've managed to buy were some $2 bills that were still in the drawer.
A teller that used to work part-time at my place of work told me that she wasn't allowed to put any of those bills aside for customers and they (the bills) had to be sent to be destroyed. She said that she had seen a lot of very old money come through her bank over the last couple of years.
How can one get access to some of these bills once they wind up at the bank? It seems like such a shame that so much of it is out of the hands of collectors.