I've never done it, but I think a battery charger and an electrolyte solution bath would do it.
You could first reverse plate the existing gold off, polish/refine the case underneath, and then re-plate it.
I'm not sure what base metal they used at Omega for plating back then... Modern gold Omega watches are solid, like Rolex always has been.
You could first reverse plate the existing gold off, polish/refine the case underneath, and then re-plate it.
I'm not sure what base metal they used at Omega for plating back then... Modern gold Omega watches are solid, like Rolex always has been.