Cats have a tendency to rub on plants. I don't think any amount of wash is going to remove that hair. Just a slow process of hand picking it off. Who wants to light up a joint containing cat hair? I think a nice green thing to do for a regular wash is to leave the plants out in a moderate rain, but GWE has warned us against that. "Cover plants when it rains, and otherwise shake them off when they're wet. Bud rot is a fungus, and like all fungi, it needs a wet place to germinate."