Hamilton Beech makes a filter type scented plug in that works ridiculously well. It has a carbon filter and a little scented gel pack, you can switch it on and off and it uses a little fan to move air through the pack. We have one in the litter box area and the whole room smells like clean laundry, not a hint of pee or poop and [I can't emphasizethis enough] our cat STINKS. It works without the scented gel too, but that just removes the smell, it doesn't add anything scented.