Honestly, your Nuovo Record / Record group appears to be in remarquable condition and would polish nicely. Don't try to polish the crankset or rear derailleur, they're anodized and you'll just mess up the finish. Dish soap and a thooth brush is great to remove the dirt and old grease. Finally, I'm not sure why you'd want to soak the rear derailleur in OA since there is no rust on it...