Well, all I can say is I cleaned it off. I wouldn't put it back on if the surface wasn't absolutely free of any oil/coolant or even rtv. After fully cleaning it, I made sure it was not warped using a metal straight edge at all angles. Before I put the head back on, I had my wife wipe the surface with a clean towel with alcohol on it. Just because I didn't take a picture, doesn't mean it wasn't done. I've got over 100 miles on it now, and not one leak or signs of an issue.