I don't want to under mind anyone's do it yourself filter, but You should pay the $100 or 2 and get a good carbon filter. Those homemade jobs just use a carbon wrap, (no actual packed carbon). This might last a week or 2. I don't mess around, I have an 8 X 36 inch filter with Australian Mined Carbon, not the cheap Chinese stuff. To me this is a small price to pay for my security.
It doesn't matter how far out you live, you never know who will show up at your door. They smell it, and after they leave they call police, & they become your next visitor.