Re: Cleaning/Polishing Portlights
They look like the Bomar ports widely used in US production boats. I'd do some investigating first as they are made of an aluminum/magnesium alloy and nothing should be done to them except clean them with vinegar. The original Bomar almags had a stainless set screw as a hinge adjuster on the hinge inside. They cannot be re-anodized because of the magnesium content if indeed they are the Bomar.