Its similar to this. Carbon or charcoal filter that traps odor instead of just masking it with other scents.

Alternatively you can just leave a tray of activated charoal(which you can find in the aquarium section of any chain pet store) out in the room and it'll do the job as well. It has a ton of surface area and just traps odor particles on the surface. When it starts to get a little smelly again just dump and refill the tray.