Cleaning Up Gauge Face Plates

I'm sure I've read something about this before, but I couldn't find anything. Also not sure if this is the right forum - technically not electrical but not really paint and bodywork either... Figured all the stuff on gauges would be here.

What do you guys use to freshen up the face plates when rebuilding gauges? Mine are a bit faded in the middle and I only have one chance with the tacho face plate as they are hard to come by (750H1 tacho with voltmeter). Really just wanting to get a consistent black background.

Here's a meter topic I started a while back that has some suggestions by others. KZR >> Refurbishing meters
Warren3200Gt mentioned a product from the UK that he uses. page 1.
asphalt900 knows quite a bit about about how to do the entire job. see comments on pgs 2, 3 & 4. I don't recall if he said anything about the black. After a quick check, I didn't see anything.

Thanks Martin, that's what I was looking for. For some reason 'refurbish' didn't come to mind when I was searching.