what to do with old nengajou

What to Japanese people do with their old nengajou? I have lived in Japan for a few years and have quite a collection of past new years's cards....Any suggestions?
thanks.

Well, you cannot keep them all - when I receive new ones and have checked the senders' address and other contact information against the previous year's cards, normally I throw away the old cards (I shred them). At least that's how I try to keep them organized... Some I do keep for many years if the photos they used on the cards were great, or for other sentimental reasons :)