Some say you can use frying oil over and over again, but for the best results start fresh. Old oil can bring flavors from the last thing you fried into your new batch – no one wants donuts that taste like popcorn shrimp.
Oil can also turn rancid over time, which has a negative effect on the speed of frying and causes your food to taste bad.
After the fat has cooled down, throw it away and. In many cities, there are recycling areas where you can hand over your used cooking fat. Whatever you do, do not pour oil into the drain. It will clog your pipes as it cools and solidifies.