I aired it outside for a week or two, then gave it a bath, then conditioned it a little, aired it out for another week, wiped down with alcohol, gave it another bath, etc. At times I've sealed a bag in a bag with bath salts which worked pretty good. I've used Zero Odor and Febreze Free - nature. Some people use vanilla vodka or aquarium charcoal. The vintage bag I bought at the end of August had a mild smoke smell when I got it. I still haven't gotten rid of completely but it is almost gone. I don't think the order matters. Everything I do is followed by a week or two of hanging outside. I think the outside airing does the most good.
Be careful about using baking soda as it is harsh to leather.
Is it harsh when dry or when the baking soda is wet? I was going to to dump in dry and then vacuum it up and then wash in dawn bath.