My valve cover on the Integra is dirty and it also has small dots of paint all over it. I guess the coating is considered crinkle paint - is that correct? I`ve tried plain soap and water, Castrol Super Degreaser, and EO A2Z Cleaner and none of them have helped removed any dirt or paint spots. I`m wondering if a fine grit sandpaper would be ok to use? Any other ideas on how to get it clean?