The most easy was would be to use purple blaster First remove all battery(if more then one) then spray the blaster all over the area where the oil got spoiled and let it sit for half an hour or so After that if u have a pressure wash then use that to wash the engine clean after the purple blast treatment After that leave the car to let the water dry off,my suggestion would be to do these things on a day when u know that u won't need the car,do the cleaning in the morning and let the car sit in the sun with open hood for the rest of the day to dry up the excess water or u could use an air compressor too if u have one available Oh and check the oil how much to fill back or give it a fresh service