The Odor Sok has a 12mm fabric of 20 nanometer fibers and should have twice the contact surface of a heavy carbon filter. Sometimes humidity covers the fibers and lets odors by but it works again when it is dried.
The absolute definite place to use it is on the intake. I put on on my intake pipe and any powdery mildew dissappeared. The Odor Sok blocks light from getting in or out like shutter and air only moves through it when the fans run. I heard about a garden over a main street getting visitors when odor got out when the fans weren't on.
The Sok is great for low intensity uses like tents, mom rooms, babies, drying areas, and scrubbing. Mash them in clean water and dry to reset them.
Making homemade filters is OK but there are different kinds of carbon and big differences between them. Remeber why you are buying a carbon filter and make the investment in your security. Phresh filters and the old Phat and Dragon Filters are the best. The new "pHAT" and phat hydro filters won the brand name in a law suit but arent the same. Too bad that kind of thing has to happen in hydro.