The best way to remove ballast goo....and also tar(usually) is essential oils and baking soda. The essential oils ( it doesn't really matter which type of essential oil, however, grapefruit and citrus based oils work best) will lift the stains without any soda but the baking soda helps to absorb the gunk once it's lifted. Tea tree oil works also but the smell is super intense and it can be unhealthy if skin comes in contact with undiluted tea tree oil.. Not to mention tea tree oil can be very fatal to pets and animals.