I use a treat, right now anyway, the soft Milk Bones, to get the dogs to jump into my....ah......hairy SUV. Sometimes after the "jump", I shut the door and give Coal and Chev one of the Milk Bones through the open window. Chev and to a certain point, Coal, drool and get saliva on the outside of my Hyundai Tucson, and sometimes it is on the inside, too. Windex with ammonia or Mr. Clean usually removes the saliva stains from the seats in the car. Washing the car with Blue Coral car wash, so far, has taken care of the outside of the vehicle. Other than that, I don't know what to suggest. We do have the "Doggie Scrubber Thingie" (Not the correct name, obviously) with appropriate "Pet Oxygen", but I haven't had to use it on the car yet. We don't have too much issue of saliva from Chev inside the house. I keep a piece of indoor-outdoor carpet covering most of the back of the car to catch the hairs of Chev...and boy, do these hairs stick to things
Best to you. Have a great Sunday !!