J.H.
I don't do anything special to store my window clings and they seem fine after a few years of use. I just stack them on top of each other so they stick to each other and put them flat in the box along with the other holiday decorations. I have used them year after year for at least 4 or 5 years now and they are fine. I just rinse them off each year before I put them on the window and they stick just fine.