If a carpet stinks enough that you'd rather be outside, it's time to do something about it. Since throwing the carpet in with a load of laundry isn't an option, freshen the carpet instead with a homemade carpet-refreshing powder or spray.
The Simplest Solution
The simplest way to freshen carpet is also one of the least expensive. Baking soda absorbs all kinds of odors that may otherwise be trapped in carpet fibers, such as pet dander, wet-dog smell and food odors. Sprinkle baking soda liberally over the offending area or even the entire carpet. Allow the baking soda to sit for an hour or two, then vacuum it up. If the area still smells a little less than fresh, sprinkle on more baking soda and let it sit overnight before vacuuming up the powder.
Homemade Scented Carpet Powder
Commercial carpet-refreshing powders often contain pleasant fragrances to help mask odors, but the other ingredients may contain chemicals. Make an all-natural carpet-refreshing powder on the cheap by mixing 1/2 cup each of baking soda and Borax, which can be found in a grocery store's laundry detergent aisle. If you have sensitive skin, wear rubber gloves while working with Borax, as it could irritate skin. Avoid breathing the powder and touching your eyes after working with it.
Mix the ingredients in a jar with a shaker top, such as a mason jar or repurposed Parmesan cheese shaker. Add up to 30 drops of your favorite essential oil, such as sweet orange, peppermint or lavender. Lavender also has deodorizing and antibacterial properties, so it's an excellent choice for general carpet cleaning. Place a regular non-shaker lid on the jar, shake it up to blend ingredients, then replace the shaker top. Sprinkle the powder all over the carpet and allow it to sit for an hour or so. Vacuum up the powder.
If your carpet stains easily, test the powder in an inconspicuous area first to ensure the oils don't discolor the carpet fibers. Since the oils are mixed into the powder, this generally shouldn't be an issue.
Even though vinegar has a strong odor of its own, it's a powerful deodorizer. The vinegar odor also goes away once the vinegar evaporates, taking other odors with it. Make your own deodorizing carpet spray by mixing one part white vinegar with two parts water in a spray bottle. Spritz the stinky area of the carpet with the vinegar solution, being careful not to soak the carpet, as this could cause damage to the floor beneath. Allow the area to air dry. This mixture works well to remove lingering odors left behind by spilled milk or pet problems, once the original mess has been thoroughly removed.
As simple as it sounds, fresh air works wonders to help keep a carpet and even the entire room smelling its best. Open windows for at least 30 minutes a day, if possible. Open curtains to allow sunlight into the room as well. Fresh air helps remove airborne odors that sometimes become trapped in carpet fibers, such as cigarette smoke or burnt food odors.