They're steel? I got to go down and check. I thought they were aluminium.
I don't have a storage option for you, since all of mine were new.
I do write with sharpie on the outside the plate # and the ammo it's used for, e.g., ".44" ".458" etc
I do have separate plates for .45 and .308, btw.
So while we're talking shell plates here's my storage ritual.
When I store a plate, I use Hornady's One Shot and thoroughly clean top and bottom. I then put just the tiniest dab of lcp over the bearings.
When I get a plate out (SURPRISE it's all clean) I put a healthy drop of Beeman Spring Oil on each bearing. This is a very high viscosity, clear lube and I hope it makes the plate turn smoother and last a long time.
Needless to say, before I mount a plate I thoroughly clean the head including all the crevasses and the indents.
100,000+ rounds and still going.