i did this along time ago it actually did work some. if you look up diy carbon filters you will find some excellent alternatives. Activated carbon, duct tape,some mesh and a inline duct fan should work great. around here an inline duct fan at my local hardware store costs about 25$ 4", 30$ 6" 35 8". you can find the duct tape there and the mesh screen, or an old window screen will work. and you can get the activated carbon at walmart or a fish store