If you have a box fan, put it in your window and totally seal around the edges (so the only way air can go out the window is through the fan). When it's on, it should be strong enough to where you can feel a draft under your door from the air being pulled out the window. You can smoke and nothing will ever get out into the hallway and if you leave the fan on long enough it will totally clear. I got away with smoking in the dorms like this. Rather than Febreeze, I'd use this stuff called Snappy Apple. One spray does a room almost instantly.