Generally Tarot cards are not kept in the original box, it’s mostly useless anyway. As is the little booklet that comes with your cards. I would suggest putting the cards in a cloth bag, wooden box, or a special container that is meaningful to you.
There’s quite a bit written on cleansing your cards. These are some of the more common methods & I have on occasion used some of them myself:
1. Smudging the deck at each new moon with incense or sage smoke.
2. Keep them shuffled & every so often put the cards back in the original –out of the box sequence.
3. Store your deck with smoky quartz, amethysts and/or psychic enhancing crystals to absorb negative energies.
4. Place them on the window sill at the full moon for 24 hours so they are cleaned & charged by both the Sun and the Moon.
I would suggest a cleansing when you first buy your deck, but please do not put them in water unless you wish to buy another deck. If you wish you can do a little ritual, prayer or meditation at this time to connect your psychic energies to the cards as well.
For even more cool info on tarot please see my facebook page, http://www.facebook.com/tarotforhealing