HI, I had a job where a grain truck tipped over in a ditch. It leaked fuel oil and radiator fluid onto the lawn. The area sat untreated for about a year. Then i tilled up the area down to about 4-5 inches and removed the dirt and replaced with new dirt. Then re-seeded. Nothing came up. The customer didn't water the are for about a week before we got rain. Any tips for fixing gas spills in lawns??? HELP!!