1 cup baking soda
A few drops of essential oil or fragranced oil
Mix the oil into the baking soda and let it sit for at least a few minutes. The baking soda will absorb the oil and take on its scent.
Sprinkle the powder onto the carpet and let it sit for an hour. The baking soda absorbs unwanted odors in the carpet and the oil will add a subtle scent. Now just vacuum it up, and your room will smell great.
Some essential oils have antibacterial properties, including lemon, lime, orange, basil, cinnamon, clove, eucalyptus, tea tree, lemon balm, peppermint, and thyme. If there is food or pet odor in the carpet, one of these oils - or a mixture - might be a good choice. In the winter, wouldn't cinnamon and cloves smell great? And maybe a sunny citrus mixture in the summertime?
If you aren't worrying about bacteria, and just want to freshen up your home, use any fragranced oil or perfume oil that you like! Today I used one called Champagne Sugar, which has a little sweet and fairly light scent. It smells so happy and pretty, and not at all overwhelming.
If you have a tougher odor, you can mix up a bigger batch and sprinkle the powder on thicker. If you can, leave it to sit overnight before vacuuming. Repeat as necessary to have a fresh-smelling home.