CD bronzing
If you’ve never seen factory-pressed CDs decay, or think it’s a myth, well, I have some photos to show you. Here’s an overall view of the label side of the CD. Notice the strange swirly patterns. That’s not a camera artifact; the label part of the CD seems to have some separation from the metal layer, resulting in the interference patterns. Here’s another view, showing that part of the label embossing has caused brown patches.