Cooking oil, when used occasionally and sparingly, may seem like one of the more affordable items in your pantry. But when you start frying up food for large groups and going through oil by the quart, the costs can add up in a hurry. Fortunately, there's a trick to deodorizing your used cooking oil so that it can be used multiple times and even for multiple types of food.
Fry one type of food in the cooking oil until you're finished or until the oil starts to look murky and scattered with burnt pieces of food and batter. Remove the oil from your heat source or, if using an electric fryer, turn off the heat. Allow the oil to cool for a few minutes.
Place a strainer over a spare pot or bowl. Make sure the strainer is stable and the container is large enough to hold all of the oil. Carefully and slowly pour the used oil through the strainer and into the container. Unless the oil has cooled completely, you must use extreme caution during this step. Wearing heavy rubber kitchen gloves is advised.
Throw away the bits of food and batter caught in the strainer. Clean the inside of the cooking pot or electric fryer thoroughly using hot water and dish soap. When the pot or fryer is clean, dry it completely before proceeding.
Pour the strained, used oil back into the fryer or pot. If the oil is still hot or warm, use extreme caution and wear gloves if you prefer.
Bring the oil back up to cooking temperature. While the oil is heating, cut a raw potato into several thick slices.
Drop the potato slices into the hot cooking oil and cook them for several minutes until they're golden brown.
Remove the potato slices from the oil and discard them. They will have absorbed the flavors trapped in the oil, so they won't necessarily be good to eat. If you're curious, however, they won't hurt you. Just allow them to cool before taking a bite as you would with any other fried foods.
Your oil should look cleaner and the flavors of the food you most recently cooked should be removed. Feel free to cook another type of food using the same oil.