Nice cases...German WWII flare cartridges are cool, just from the sheer numbers of varieties you can find...I will take a shot of the various ones in my collection. I have a few live ones, but mainly empty cases.
One of the things I do to "restore" them, I fill them with sand, make a cardboard disc to close the mouth, the simulate the wax seal. I used to use real wax, but could never find one with the right consistancy, then I hit upon using Elmers white glue...I simply leave some space between the cardboard and top of the case, and flood fill it with white glue, the roll it gently to distribute, and let it dry for a few days. You get a perfect slightly concave seal, then I paint it with the proper color, and voila, a "live" flare....