Perhaps keeping them sealed in that container is causing it. Could be some kind of chemical reaction from the stagnant air.
I brought home a nice office chair that had been sitting in a smoky garage for who knows how long. It reeked of smoke even after cleaning. I've had it for two weeks and I can barely detect anything now, even when sniffing the upholstery directly. However, I'm still going to refer to it as "Old Smoky".
I've read good things about that BIN sealer though. It would be especially useful following what I'll call a redneck Retobrite treatment. I've heard of a few having success using just Oxiclean and water. Use double the maximum amount of cleaner called for, immerse object and boom, done.