I recently saw a demo for ZoopSeal but can’t say whether it works as promised or not…sure looked good though.

Other options would be clear spray paint (automotive stores carry it for wheels which might be good), clear powder coating, or anodizing (used alot on 1960s cars with aluminum trim).

I would try the Zoops first then the spray paint since the cost wouldn’t be expensive and the paint easy to strip if needed.

The last two options would probably outlast the first two.