I primarily use smudge sticks and incense once a month for this. Say some prayers, light some incense or sage, and pass the decks I have recently used (along with some crystals too) to cleanse them. I use crystals primarily for meditation and for their energies, although I think they do have cleansing properties.
After I read, I almost always have enough time to arrange the cards in the deck I used. This way, I feel that the energies of the previous readings won't have any effect on future ones. If I feel that a reading is particularly exhausting, I clasp my deck between my hands while I say my prayers. I feel that this is a good way of grounding myself and pacing the energy of the cards, like drinking a glass of milk before one goes to rest.
Toda la vida es sueño, y los sueños, sueños son