When I started the collection I  used glue to put them on wooden plates and hang them on the wall, it was a nice picture to look at but when I had about 5000 diff. caps the wall I used was not big enough so now I store them on wooden plates 40x40cm (approx. 15.5x15.2 inch). These are stored in cupboards holding each 36 plates, all sorted out country by country and in alphabetical order.

I also frame the complete sets in a wooden/glass frame and display them on the wall so you have a nice look at some of the most beautiful caps