Looking for some advice on restoring some luster to the vinyl door interiors... As you can see in the image below, they're in good shape, but there's a lot of sun baking that's occurred over the past 50 years and you can see the lightened areas in the valleys of the patterning. I'd like to bring this back to solid black... I know there's vinyl dye (AKA glorified spray paint) but this seems like overkill for this job. It seems like the ideal tool to throw at this would be some sort of compound that could be "turned" in, much like how shoes are polished. I'm not suggesting using shoe polish on this(!), but I wonder if there's a similar tool to tackle small interior sections like this?