As a non-white man from a tropical country now living in a colder state in the USA, this is somehow me too.

This is how it looks after a bunch of soap and scrubbing with a new toothbrush.

This feels chemical for sure. Mold probably would have come out by now I think.

Thank you so much for going so detailed! That is so much good information and brainstorming. I washed it with soap - it still stays, I doesn’t go away or even reduce a bit.

Spray - possible. My cleaning people come over once every two weeks and clean windows and blinds as well. This vent happens to be right above a window.

I also run a humidifier in the room at night. No other room has this much gunk on it. Only my room does. So that could be one more contributing factor.

The substance is not oily. It is not powdery either. It seems like almost etched into the plastic - this may support your spraying theory: someone cleaned something nearby with sprays that could damage acrylic surfaces.

That was a good investigation! Awesome person you are!

There’s a better joke in there somewhere. Sleep on it.

Yo Dang.

This might be a bit sketchy.

I’m mostly sure before our surface cooled down it was hotter. Or when we had no ozone or when moon formed.