I haven't bought from JFA yet but have considered it. The bags are definitely very used but if the right bag comes along at the right price, I'll just consider that it has to be taken for a spa treatment. It will still cost less than many other bags out there. The Chanel bags I have seen are all authentic so far...bt you do have to check their description and ALL the photos.
I don't know where they store the bags but certain areas of Japan are very humid so mould can be a problem and I suspect that as they are handling huge amounts of bags the bags are in some warehouse...
FYI a lot of vintage bags bought at Paris sales also tend to be smelly.
BTW apart from airing the bag and giving it a good clean try the following eco-friendly tip which works really well for smelly shoes and boots: Dried thyme leaves wrapped in a small cloth or just as are ( remember to clean out well after) and leave in the bag for a few days to weeks. Thyme is a natural bactericide and disinfectant.
I know this post is very old - but thank you for this very useful tip!!!