eolian
Some Spanish tarot readers cleanse the deck with cigar smoke.
I wonder if it's actually the wax then - maybe it absorbs stuff ?
There have been some very good suggestions in this thread, from physically cleaning the deck (perhaps using talc), sunning and airing, freezing in a ziploc bag, and use of scents (that order seems about right).
I would like to draw readers' attention to a French type of scented paper, "Papier d'Arménie", a now-traditional remedy to unpleasant odours made from strips of paper dipped in benzoin resin.
Burn a strip of the paper to purify the atmosphere - it really does cleanse the air instead of simply masking the smells. Benzoin incense is also used in Eastern religions for purification of a less physical kind, and it is commonly used for this purpose by French Tarot readers too.
Also, a few strips placed between the pages of old books can help remove musty smells. I keep a strip or two at the bottom of Tarot boxes to keep the decks fresh.
This paper is now available worldwide through online sellers, for example, Amazon.