why wouldn't that be optimal? archival negative sleeves would be my first choice. I've found 150-year-old tintypes that were stored in horrendous conditions -- usually antique albums made of really poor quality paper -- that look perfectly fine. I have a bunch of antique ones that I keep stacked loose in a brown paper bag in my darkroom. Those pressed paper frame box thingies with the gold frame were not a lot better, archivally speaking.
I mean, they;re tin, they're protected by varnish or some other clear coat (usually) but even if not, they shouldn't need any more protection than any other photographic object. Something to keep them dry and from getting scratched. Archival negative sleeves would do the trick. Keep them in a file box that stores them on edge, keep them dry and cool and dark, they'll be there in a couple hundred years.
