Your iPod’s paintjob is made up of rust
You probably own a buttload of metal gadgets, with a bunch of iPod’s from before your phone could play music. Chances are the paint on them is still nice and colorful. But did you know this was due to a thin layer of rust allowing the paint to stick in easier, and be tougher?
It’s really quite simple, Apple first oxidizes (or, in layman’s term, rusts) the surface of the gadget, enough for a honeycomb of holes to be created. Then, a dye seeps into the holes, and the iPod casing is boiled to lock the color in.
The metal seems as if it’s painted, but in reality it is actually a part of the metal. It’s a very interesting concept that technology makers use to brighten up their hardware palette.