I like this method of presenting my small works. The shadow box is made with a deep moulding. Archival foam core is cut for the side and glued to the wood (a few drops of rubber cement). The back sheet is white foam core that sits on top of the side pieces of foam core. I use mirror clips and small screws on the back to make for easy reframing. If the piece that's showcased in the frame is rather heavy I use drops of rubber cement as the adhesive. For best results reapply 2 or 3 layers of cement, let dry between coats and press down (I use a stack of very heavy books to apply weight). You can easily remove rubber cement for reframing, without any damage, and it doesn't mess with any of the archival materials.
I like the look of these framed, and perhaps one day I'll do shows again, but for the moment I'm happy to send these off in the mail unframed to my customers who find me on Etsy.