A simple household method involving vinegar, salt, and water has been passed around for years as an inexpensive way to make a room feel fresher. The idea is straightforward: fill a glass with water, add some white vinegar and salt, stir briefly, and leave the uncovered glass in a room where unpleasant odors tend to linger.

Vinegar contains acetic acid and has a strong odor of its own. It can be useful as a household cleaner and deodorizer in certain situations, although leaving a glass of diluted vinegar in a room isn’t a proven substitute for an air purifier or proper cleaning.

The salt doesn’t magically remove toxins from the air, either. In this mixture, it mainly dissolves into the water. Some people notice that the room seems less stale after several hours, but stubborn smells usually have an underlying source—such as food residue, garbage, smoke, moisture, pets, or mold—that needs to be removed rather than simply masked.

If you want to try the method, place the glass somewhere stable and out of reach of children and pets, and replace the mixture regularly rather than leaving it indefinitely. Ventilation and cleaning the actual source of an odor will generally make a much bigger difference than the glass alone.

One important warning should never be ignored: do not combine vinegar with bleach or other household cleaners. Vinegar is acidic, and mixing acids with chlorine bleach can release dangerous chlorine gas. So while vinegar, salt, and water may be a simple deodorizing experiment, it should remain completely separate from other cleaning chemicals.