Thanks KDV, these are oil stains that are completely picked up on the surface but have left a stain that doesn't want to come out. Over the years I have tried lots of stuff with no real success. I just saw a video on you tube where a guy used Carb cleaner and that seems to work pretty well. I may try that just to add to the list. I have also never tried power washing it, anybody ever tried that? Anyway, thanks for the suggestion.