To use a CarCologne car diffuser air freshener, first unscrew the lid and remove the inner stopper. Replace the lid securely and tilt the bottle upside down for 3-5 seconds to allow the fragrance oil to seep into the lid. Adjust the string to your preferred length and hang the diffuser with the lid pointing upwards. The scent will be released slowly over time, and even when the oil is gone, the fragrance will persist for weeks or months. If the scent weakens, briefly tilt the bottle upside down to release more oil into the lid, but avoid doing this too often, as it may cause leaks and deplete the oil faster than normal. For more information (and even an instructional video), please see our complete guide.