Simply rub a small amount of O-P-I above the upper lip and it will selectively target and block the offensive odor of decomposing or burned flesh. However, it will still allow the full gamut of additional smells through, allowing you to detect subtle olfactory clues without overwhelming your senses with the smell of putrefaction. Available in individual-use pouches, the product can be carried in a shirt pocket. O-P-I has a mild, vanilla scent.