After 5 days drying on wax paper, I put my bubble in to a small glass jar. I wasn't sure if I was supposed to put a lid on it at this point, but I did anyway, and discovered a moldy jar of hash a couple days later. Dumb mistake. Anyway, my second batch has dried, and it's been sitting in a small glass jar *without* a lid on it for well over a week, and the stuff is still like butter. Very fresh. My relative humidity is around 50%, and I have a hunch I could leave this out without a lid on it for at least another week or two and it would still be very fresh, primo hash.
This is probably captain obvious material for most of you, but I thought it was worth pointing out to any bubble hash newbs like me.