I do not leave them in the original box, as then I have to go get the original box...and, like many of us, the boxes - not the engines - are in the attic....there aren't that many sizes/widths/depths, so I just find one that fits, but it does make more sense to have a simple tagging/marking system. I should have, but I didn't.
Above:
"I recall storing regular rubber bands in a paper bag with talcum powder, wonder if that would keep a supply of traction tires fresh?"
Not sure how "fresh" one can keep these, and, so far as I know some were/are made of rubber (not good, long term) and some are made of neoprene (good all around - including being unaffected by oil-based products...like oil). Neoprene good, rubber bad.
The talc used in rubber bands is there to keep the rubber bands from sticking together, as talc is a dry lubricant (talc is a natural clay).
So, the effect of talc is to eliminate the traction between rubber bands, so the last thing you want on your traction tires is talc, which could leave the tire, but little traction. The main problem would be the grip the tire has on the wheel, as the rail surface side should shed the talc fairly quickly. In actuality, it probably wouldn't be a biggie, but it's still a fact.