I keep one of each pin that I design, and originally I had them all displayed on a cork pin board. That was all well and good when I had about 30 designs but now that I'm nearing 200 I realized I needed a better way to store and/or display my collection. Now that I finished this project I think I'm going to do the same thing for my embarrassingly large collection of Disney pins, too!
I found these jewelry cases on Amazon, but really any case meant for displaying rings or brooches should work fine. The fabric in the case has a cork/cardboard like backing that is perfect for securing my pins in place. I just make sure that I attach them in between the rows, not inside of the groove, or else they won't be secure. Each case holds about 60 1" - 1.25" pins, give or take.
Since the pins attach securely into the case, I can choose to display the case upright on my dresser along with my other brooches and jewelry! Or I can stack them up neatly and put them away for safe keeping. I love that the glass lid keeps them dust-free but also lets me see my whole collection at a glance.
I hope this little DIY tip gives you some ideas for how to store your own lapel pin collections! And if you're like "wow, I love this idea, but I need to build a pin collection first" (wink wink) they're buy-3-get-1-free in my shop right here.