I still had some 13*13*1cm activated carbon filter sheets, so I decided to design this filter housing, it uses 6mm magnets, I have 5 of 0.9mm thickness stacked in each corner, it's what I had laying around. Attach it over the case fan exhaust.
Can use one or two sheets, cut them to 9*9cm. I personally use two. It helps a lot with the smell.
AliExpress link to such filters, or just search for activated carbon.
The author marked this model as their own original creation.