I recently stayed in an apartment that didnt have central air so I created a corsi-rosenthal box since the smoke from the Canadian wildfires were so bad.
After 30 days of continuous use, with very minimal periods of it being turned off, this is what the filters look like!
It's disgusting yet also so satisfying to see the filters get darker from debris, dust, and dirt.
Edit: typos
I've put an air filter in the bedroom next to the bed. Makes nice white noise too. I also have one next to the cat's litter box. I'm thinking of putting one in the bathroom because the toilet paper makes an insane amount of lint that builds up everywhere.