Sunlight has nothing to do with case color fading. Abrading them does remove them. Repro Parkers are hard to color because the lump the floor plate attaches to is braised on and not forged. The copper, tin, zinc contaminates the heat treating furnace and spoils results. This info was provided to me by Oscar. He had to redo his home made furnace to get rid of the bronze alloy that contaminated his fire brick.
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