If you go to a janitorial supply store, you can get these small solid "pucks" that are often used in public toilets in wall fixtures. They are called EZ Vaportek disks.
http://www.vaportek.com/
If you get the "neutral" one, it doesnt smell like too much but does work to neutralize odours. They come in a cinniamon amd vanilla scents too
My parents used to use them when they had company coming but hadnt had time to wash the carpets downstairs where the dogs were. They had several large dogs, one of which was a hound. Just one of these pucks nearly eliminated the "dog fur smell"