Consider picking up a can of
Gibbs Brand Lubricant. It's an effective rust inhibitor and overall conditioner. Was developed by a Harley builder (although no amount of any kind of spray can improve a Harley). It will work probably better than any other treatment you can find out there.
This stuff is eerily effective, not just on alum and metals but plastics, rubber (trim, hoses), electrical connections. The more you spray it on metal the more the metal will 'drink' it and become that much more rust resistant. You can paint over it too.
A bit of a product-whore, I know, but there's a lot of superb products out there that when found, are treasured.
Company blurb:
"
Gibbs Brand Lubricant is the first patented product of its kind designed to lubricate, stop and eliminate corrosion, displace moisture, penetrate, clean and provide long lasting protection."
Sample sites (try Amazon, Ebay, etc.):
http://www.gibbsbrand.net/http://www.gibbstuff.com/