When I've had sneakers for a while, and I'm not concerned about whether washing affects them, I just toss them in the washer and even the dryer to boot. Now I've got a new pair of tennis shoes, and they've gotten dusty from walking on dusty trails. So, they're lightly dirty. How do you take care of this? Do washing machines affect the compression/padding of the sneaker at all? Does it affect the leather adversely? What's the best way to simply clean the exterior of the shoe?