For fresh stains that are still wet, cat litter is useful for absorbing the excess oil, while pressure washing can take care of older stains that have soaked in. Sodas such as Coca-Cola are useful as an overnight soaking solution to help remove stains.
When using cat litter to absorb spilled oil on asphalt, let the litter sit on the affected area for several hours before sweeping it up and rinsing the area with water. If cat litter is not available for fresh stains, simple soap and water solutions are also effective. For older stains, using laundry detergent and a wire scrub brush can help.