Hey Bob,
If you're just planning on tossing the tape that's on the aluminum reels you don't really need an empty reel to put it.
Just take the reels apart and the tape will stay on the hub (the reels are just screwed together).
Once you just have the tape on the hub, you can usually just pull it off or if it's sticky tape, you can cut it with a razor knife and pull it off.
I bought 50 1/2" reels of old Ampex 456 a while back. It was so stuck together that even after I cut through an inch or so of tape, I still had to use vice grips to pull the tape off. Needless to say, it made disposing of it much easier since I could take one of those circles of tape and hit it against a wall as hard as I could and it hardly even dented it!
Of course, if the tape has something on it you might like to save, forget about all the stuff I just said. (The story about the 1/2" 456 is one of those tales that I seem to enjoy telling over and over again to whoever will listen.)