Start by ensuring your oregano is completely dry. If you have fresh oregano, you can dry it by hanging it in bunches in a warm, dry place away from direct sunlight, or laying it flat on a clean surface until it's devoid of moisture.
The general rule of thumb is to use a 1:1 ratio of dried oregano to carrier oil. However, you can adjust this depending on how potent you want your oregano oil to be. More oregano will result in a stronger oil.
Place the dried oregano in your glass jar, then pour the carrier oil over it until the oregano is fully submerged. Stir gently to ensure all the oregano is coated with oil.
Seal the jar tightly and place it in a spot that receives gentle, indirect sunlight or in a warm room. This warmth helps the oregano release its essential oils into the carrier oil. Let the mixture infuse for about 1-2 weeks, shaking the jar daily to mix the contents and promote extraction.
After the infusion period, strain the oil through a fine mesh sieve or cheesecloth into another clean, dry glass jar. For a clearer oil, you can strain it a second time or let it sit overnight and then decant the clear oil from the top.
Store your homemade oregano oil in a dark glass container to protect it from light, which can degrade its quality. Keep it in a cool, dry place. Properly stored, your oregano oil can last for up to a year.