To do a warm oil infusion, fill a slow cooker to about half full with hot water. Place the tightly sealed jar in the slow cooker and turn the slow cooker to the warm setting. Put the lid on the slow cooker.
Allow the herbs to infuse in the slow cooker for 8-10 hours. Then strain using muslin cloth or a fine mesh strainer.
Store your infused oil in a clean sterilized jar. For the best results, store it in a cool dark place, such as a cabinet or closet.