My questions would be, is that mold or crystals on the tobacco (I can't tell from the picture) and did the rust expose the blends to air from outside the tin, which would make it probable that the white stuff is mold. I don't think you want to smoke mold. If you want to be scientific, you could put a small quantity of the white stuff in a jar with some bread and see if it grows there -- that would be mold. If I looked it over, in person, and didn't like its looks, I'd toss it. The photos don't look appetizing to me.