How do I remove metal coatings on CD without scratching the surface?
I think that you mean that you want to use the foil as a diffraction grating, not the plastic part. Some of the cheaper CD’s will come apart – into three layers – rather easily if you bend them into an arc. Sometimes the plastic breaks in the process, but I think that might be your best chance. If you do not necessarily need the entire piece of foil as a diffraction grating, you can try to crack the CD in half, and try to pull the plastic surfaces apart, releasing the foil center.
