I personally have a homemade deionizer in the room where I smoke. It'll smell for the first hour - two or so after smoking, then it just goes away. Though back when I was smoking in my room at my parents house I just took a paper towel roll * used up of course* and shoved 4 dryer sheets in it. Take a hit and blow it through the tube, works wonders in compilation with bongs for insta-smell-be-gone.