I'm certainly not the authority on this, but I don't think you want to take them down to bare rubber. They need the cushioning to get a good stamp. You can buy a sticky-backed cushion that has the cling side for the acrylic blocks, but I really don't think you'll need it. The few rubber stamps that I've unmounted have had enough sticky left from being on the wooden block to stick to my acrylic block but are no problem to get back off when I'm done. I haven't used DVD cases, but they stick to the surface of the inside of my CD cases that I've used just fine.
I'm actually going to be putting mine on 8-1/2" x 11" sheets that are made to hold cling stamps. Only, I'm going to cut the sheets in half and store them in plastic containers I've bought that are just the right size and have a lid. I tried putting them in binders, but even with the stamps and sheets in a page protector, I managed to loose a few smaller pieces of stamp sets. I plan to number each sheet, put it in a cut down page protector, then just make a catalog of each sheet with the stamped images and the number. Does that make any sense? I have so many stamps (many of which I hope to eliminate as I do this) that I would need a tremendous # of DVD cases and someplace to store them. I just don't have enough room.
I hope someone can give you more definite answers, but maybe my answers will help a bit,
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