Here is what happened with me. I had a dice display on my wall which was 1/4 in molding with a layer or archival board on top to sit the dice on. I started to notice some dice deteriorating so I decided to keep them in plastic pill containers. I think some how this created moisture and they were deteriorating faster. They were getting a wet slimy feeling. So I removed them from the containers. I now have them laying all apart on glass until I decide what I want to do with them.

When I had them on the moldings I never let them touch. They were touching in the container. I think at this point it doesn't matter.
Barry