I am sort of divided on this one myself. I don’t particularly believe that decks have energy that would need to be cleansed or charged, but I think that people defiantly do. On the other hand there are certain habits I have that would suggest otherwise.
I do keep a crystal/stone with decks that I store in a wooden box, and use most often. I forget where I got the idea from, but I have always used either amethyst or apache tears. I don’t know if I actually believe it does anything for my cards or the readings, but I just have always liked the ritual.
Also, if a reading feels off or the deck doesn't feel right, I am more likely to blame myself then the deck. In cases like that I find just shuffling for the sake of shuffling to be helpful for me. I think it is a very meditative act, and reflective as well.
When I first started to study tarot, and would read for people, I would let people handle my deck(s). However after time this has changed. As my own collection of decks grew, and I started to really love certain decks, I became more and more agitated at the sight of someone else handling my decks. Especially when they would start to shuffle them like a regular deck of playing cards, or swish them around on the table. I don’t know if this effected the cards energy as much as my own!
I have also acquired the habit of doing a reading for new decks, for the deck itself. It is a single card reading, and intended to give me a feel for the deck, and ways I may use that particular deck.