We have a nice kitchen vent hood over our range. We had it installed in 2018 as part of our kitchen remodel. I’ve been cleaning out its grease trap from time to time, but I’d never removed the housing and cleaned the actual blower until last week. I didn’t realize I was supposed to until I saw it mentioned somewhere. Wow, that was way overdue. When I got the blower out and could see it clearly, it looked like it was growing fur. Apparently that’s a combination of aerosolized grease, household lint, and heat polymerization, layered up over the years. In Gemini’s words, it’s “essentially a felted carpet of kitchen grime.”