Send me your media and I'll find metalI wick the media, then inspect it with a 10X loop under strong light. I never see any metal particles.
I don't wick my filters or use a magnifying glass. In bright sunlight the metal is obvious. If you inspect the media indoors, it probably looks free of metal.
I'm not talking about large metal flakes, I'm talking about tiny, but highly reflective bits of metal.
Look back at every filter element I've posted here. All had visible metal when using bright sunlight.