[Overdriven]

The castrol super clean won't pit the aluminum like oven cleaner will, at least on the alum I've done. It will take away any shine, making it dull and in need of polishing. Now that I think about it more, on a motor, I'd use a scotch brite pad like linc said, or a buffing wheel with a medium compound to take off the anodizing. Either will leave a finish that isn't too rough and will be easy to polish up if wanted.

As far anodizing being tough, I was refering more to its abrasion resistance. That's why I think even something with as little abrasiveness as a buffing wheel with a medium compound would be worth considering in your case.

Either way good luck and post up when you're done. And thanks for making me want to change my motor color now!