Seeburg R (possibly others) aluminum title strip frame protective coating

Trying to remove scratches and polish the aluminum around the title strip frame but there is a hard, clear coating over the aluminum making scratch removal very difficult. Would anyone know what was used as a coating. I thought it may be an acrylic, lacquer, epoxy, or power coating, but does not come off with various solvents or heating. It does not appear to be plating. Would like to remove scratches to improve frame appearance but seems that sanding is only option for coating removal.
Thanks.

Hi Steve,
I think they used some type of "varnish" on them at the factory--but remember, those are 60+ years old now--who knows what MAY have been done, to them later on ?? Ron Rich