Lighting candles or incense will do a great job to kill smells because the flame will burn away a lot of the odor. A good ionic breeze air freshener will also do the trick. If you think the smell is in a carpet or rug try a rug powder followed by vacuuming. Leaving the windows open for an extended period of time will also help, but I would do that AFTER any incense or candles because it will help clean the air of any burnt odor.

Another thing to consider is charcoal. It absorbs odors well. Also, be sure to dust and clean all the surfaces in the room to help remove any lingering odors on furniture or hardwood floors.

Oh, and don't ever invite the smelly foot person to your home ever again.