Paper is absorbent, so the card will take on the scent of whatever is around them. Hence the reason many of our decks smell like the incense we keep in the same drawer!
My suggestion would be to put them in a loose mesh bag and keep them in a box or drawer that has other good smelling stuff in it --- pot pourri, candles, incense. Whatever you like.Shuffle them every now and then, or give 'em a shake so there will be different cards on the tops and bottoms. My guess is that the smell will be gone in a few days.
I would be reluctant to get anything ON the cards, like the chemicals from a dryer sheet, or baking soda, and especially not oils. But I might just be super paranoid!