Is is possible to clean up vintage Le Creuset Pans?

I was cleaning out my parent's kitchen and found a couple of old Le Creuset pans. I was able to clean the insides pretty well--they now perform beautifully, but the outsides are blackened from years of neglect. Scrubbing with Barkeeper's Friend and similar cleaners has no effect. Is there a

How to Clean Your Le Creuset Enameled Cookware

Stand By Your Pan – Don't Throw Away that Le Creuset! » Adri Barr Crocetti

Set includes: 1.75-quart Cast Iron Saucepan, 5.5-quart Cast Iron Round Dutch Oven, 10.25 Cast Iron Skillet, 8-quart Enameled Steel Stock Pot, 4-quart

Le Creuset 16 Piece Cookware Set (Oyster)

The enameled cast iron Signature Saucepan is a kitchen staple perfect for making sauces, but also for side dishes, preparing grains, poaching, simmering, and reheating. The smoothly curved interior and rounded base are ideal for stirring and reducing sauces, while the extended helper handle and a contoured main handle provide added control for maneuvering from the kitchen to the table.

Le Creuset 2.25 Quart Signature Saucepan Artichaut

Enameled Cast Iron Cookware – SUBURBAN POP *

Breaking Down Le Creuset's Cookware Lineup

Need help to identify this cast iron pan - Cookware - Hungry Onion

How To Clean Le Creuset Enameled Dutch Oven: Stained Or Burnt

Is Le Creuset Worth It? All About The Famous Dutch Oven