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
Christ i wish we could get these filters in au at non-arserapey prices
have you heard of the Ikea Starkvind filters? they're a bit smaller but you can tape together as many as you want