I've never had an escape before..and this one won't be my last..I'm hooked! But I wonder...is there anything you can do to keep the back clean in mucky weather? Even after I've just washed it and driven it home on dry roads the back is already accumulating a layer of dust. My husband says that's very common with flat back vehicles (he's a transport driver). Are there any after factory addons that slow down the gunk buildup?