From the Make Flickr pool, linux-works shares his secret for making dull instrumentation knobs shiny.
I bought a very old (1960's or 70's, roughly) power supply from eBay, in need of rejuvination.How to restore shine to faded knobs
Look at the two red knobs, top group and bottom group. both knobs were removed from the device, very thoroughly cleaned with hot water, soap and a sponge, then air dried. I was hoping that simply cleaning the knobs would be enough. it wasn't.
So, how did I get the top knob pair to be so nice and shiny?
Triple antibiotic ointment!
The stuff that comes out of a small tube that you use on skin cuts before you put a bandage on ;) it has a vaseline like base and this appears to bond (?) to the plastic or somehow refresh it.