In the case of emergency, you can infuse the herbs in oil with heat using double boiler. Place the jar with herbs in the double boiler and bring it to a slow simmer. Heat the mixture to a temperature of 50 degrees and keep it at the heat nice and low for 5 hours of simmer time to allow the herbs to release their medicinal properties.  If you are really in a hurry, I would not go below 30 minutes simmer time.  Remove the oil from the heat, strain the mixture with a muslin cloth, let it cool to warm. Again check the temperature of oil on your hand before applying into the ear. In case of emergency, you might want to strain just a few drops of oil for immediate use and leave the remaining mixture for additional hours.