Thanks! I started with a base matte black--you can do whatever brands you want, it's fairly forgiving. After that I used a (cheap) paintbrush and destroyed the brussels so that they frayed in every direction, and then I trimmed that. I used some flat grey paint (acrylic, but again it doesn't matter) and dipped the brush into that, wiping the excess off on the bottle. From there, I dabbed the botched paintbrush onto a piece of paper until I could barely see paint coming off. Then I just dabbed dabbed dabbed onto the black surface at different angles until I was satisfied with the coverage. Once that is almost dry, go over it again and lightly smear the paint in every which direction, not too much smearing or it looks bad. Once that's all dry and set, I clear coated with Mr. Super Gloss with 3 coats. Your favorite gloss coat will work, but controversially 2k clear would be best.
Once the technique is down, the gloss coat really makes the piece look convincing.
This is only my first attempt, so I'll keep practicing and varying everything I do. To get a more realistic look I think picking multiple different shades of grey would be nice, layering them from lightest to darkest on top. Alternatively, maybe an aluminum color or metallic would be cool. I just wish I knew how to make a perfectly good gloss coat.