You cannot "re-anodize" aluminum and expect to get any sort of an even finish. The whole mast would have to be acid dipped, then dipped in an anodizing tank. The anodizing process is an electro-chemical process that changes the molecular structure of the exterior of the aluminum. If you want to refinish it, paint, and a REALLY good paint would be your best option (like Imron). Alternatively, you could have it powder coated...but even that will have a hard time holding up as any future corrosion will cause big blisters.