How to remove drums with out destroying them???

OK I have been collecting spare hub and drum assemblies for my dart. Well I have been trying to remove the drums from the LH threaded hubs to save. Well I can not seem to get them off with out putting them in a press and pressing the hub out of the drum. And it ruins the drum, as the middle bends down in before the hub is released. Is there a better way? Or is it just a fact of life that when you remove the drums from the hubs they are scrap? Thanks for any ideas!