Add 1-2 tablespoons of baking soda to 4 cups of water in a small pot. Stir to mix. Set pot to simmer for at least 30 minutes. The baking soda will absorb odors in your home and the simmering water will add a bit of moisture to the air. For a nice fragrance, you can add a few drops of essential oil or liquid potpourri. A small slow cooker works well for this, but a small pot on the stove is just fine.
This solution can do double-duty too. If you have any liquid left, pour it into your sink (with the stopper in place), let it sit and cool for a bit then scrub. Pull the plug and rinse. Your sink is now clean!
Note: Can also be used to clean the toilet bowl (pour it in slowly).