Just repasted the CPU and GPU coolers in my brother's PC, which we realised was built during (and has remained relatively untouched since) Obama's second term in office, the dust was so thick on both that I could - and had to - peel it off with tweezers but thanks to the dust filters I installed on day one the rest of the interior was remarkably clean, all things considered. Although those filters were almost completely clogged too.
Then when it came to my own PC, there was a sprinkling of dust on the inside of the glass panel where, I suppose, the proximity of the huge CPU cooler slows the air enough for dust to "precipitate", but other than that there was just a very thin layer on the horizontal surfaces. I also decided to replace the single 120mm front fan with two 140mm ones, I went with Corsair ML140s mainly out of curiosity, but needed an Akasa PWM fan splitter since those fans have to be PWM'd as the maglev bearings need 12V to actually work.
I'm not even sure why I did it because the cooling was fine and I haven't turned the PC on for over a month at this point and probably won't until I move again (and my Steam Deck might arrive before that, even), but it was pretty satisfying. Depending on how it sounds I might replace the exhaust fan with a ML120 Pro (the non-pro has a grey propeller in a black frame, the Pro is black on black and can be seen much more easily than the front fans).
Still haven't pulled the hard drive out of the iMac, it's almost as if I really can't be bothered.
