Fuel additives are added to gasoline/fuels to enhance properties and provide additional properties not present originally. They are used as combustion modifiers, antioxidants, corrosion inhibitors, and deposit control detergents. Some common types of additives include acetone, ether, nitrous oxide, nitromethane, butyl rubber, ferox, oxyhydrogen, and ferrous picrate. Additives provide benefits such as stabilizing gasoline to reduce hard starting, preventing fuel line freezing, boosting octane, cleaning fuel injectors, lubricating valves, preventing fuel gelling, improving conductivity, deactivating metals, enhancing thermal stability, inhibiting corrosion, and reducing risks like static discharge and fire.