How do you freshen up old unleaded?

To freshen up old unleaded gasoline, you can mix it with fresh gasoline in a ratio that dilutes the older fuel. It's recommended to add fresh fuel at a ratio of about 1:1 or 1:2, depending on how old the gasoline is. Additionally, using a fuel stabilizer can help improve the fuel's combustibility and prevent issues in your engine. Always ensure proper ventilation and safety precautions when handling gasoline.