I am posting this in response to a question that was asked on a MB I belong to. A member there was looking at new ways to store her UNMOUNTED stamp sets.

This is the binder I am storing all my stamps in right now. It works great since it is a 12x12 binder. I use Memory Makers 12x12 photo page protectors to store my stamp sets in. I love that I can store 6 'sets' on a page

I also really like that the inside of the front has these 2 zippered velcro 'pockets' that hold the inkadinkadoo stamp sets perfectly.

I cut down sheets of acetate (ie overhead projector sheets) to about 4 x 5.5 and then on one side of it I stamp the images in black staz on and on the other side I brush on Aleen's Tack-It over and over, so the stamp sets will stick to it. I also leave the brown paper backing on all my Stampin' Up sets. I am hoping in this picture you can kind of see the blurry part behind the stamped image, that is the tack it over and over

I have a few stamp sets that were given to me by other people (this one from my SIL Catherine, thank you!!) and those were mounted when I got them. I took them off the blocks and most were still tacky enough to stick to the acetate sheet, so those I left alone. The few that didn't stick I put the tack-it over and over on the back of the acetate sheet like the other sets.

I hope this explains well how they are stored. If you have any questions please leave me a comment and I will try to answer anything you need to know.