I get rid of every copies. Personally, I don't see the point of the storage about my materials... I've got the original WAV, and/or tape masters + original artwork/or with the prints. So, I listen them, if I want to listen my own stuff, and not the issues. Also, 2-3 near friends always have a copy of an issue, so, if I would need the release material for something, I still can get them.