Except for plastic, this coating sticks to almost anything but oil spots are definitely a problem. Best use a citrus based de-greaser, full strength , let it sit for a while , rinse and repeat a couple of times. If available use power washer on those areas. Let dry and then apply two coats. If the coating still does not adhere, you can cut the problem spot out, de-grease again. I had an area in my trailer soaked through the floor. I just replaced that part of the floor.