Hey, my K5 is marking it's territory all over my girlfriends driveway. The thing of it is, her parents are going to freak out over this because the driveway was only put in about 1 year ago and they helped pay for it. Whatwould you guys use? I was oging to try carb cleaner, brake cleaner or Works(with Hydrochloric acid), but I wasn't sure if these would harm her concrete driveway.. Anyone???