I see you've been enjoying our unusual weather today, too!
I'd suggest you head for a Pep Boys or an O'Reilley Auto Parts and ask for some products from "Mother's". Many of their products are designed to bring aluminum wheels back to new appearance, others are designed to be used for polishing to a brighter finish.
Murphy's law in action....we get NO rain for 6 months, and the day your Cobra arrives it rains all day.....just wait, though, the clouds will leave and then you'll be able to enjoy our delightful fall weather for cruising!
Cheers, Dugly