The best oil to add to a new Zippo lighter is lighter fluid, specifically Zippo's own brand. This is because Zippo lighter fluid is specifically formulated to provide the optimal flame for the lighter's design. It is a highly volatile, flammable liquid that is designed to ignite quickly and burn cleanly, ensuring a reliable flame for lighting cigarettes, cigars, or other items.

The reason Zippo lighter fluid is the preferred choice is due to its high volatility, which allows it to ignite at a lower temperature than other oils. This is crucial for the Zippo lighter's design, which relies on a small amount of fuel to create a strong flame. According to a study by the National Fire Protection Association (NFPA), lighter fluid has a flash point of around 37°F (3.3°C), making it highly flammable and ideal for use in lighters. Additionally, Zippo's lighter fluid is free of harmful additives that can damage the lighter's mechanism or produce an unpleasant odor.

Using other types of oil, such as kerosene or gasoline, can be dangerous and detrimental to the Zippo lighter. Kerosene, for example, has a higher flash point and is less volatile, which means it takes longer to ignite and may not provide a consistent flame. Gasoline, on the other hand, is even more volatile and can cause the lighter to overheat or even explode. The NFPA also advises against using gasoline in lighters due to its high risk of fire and explosion.

In conclusion, Zippo lighter fluid is the best choice for refueling a new Zippo lighter due to its high volatility, low flash point, and compatibility with the lighter's design. It ensures a reliable and safe flame for lighting, while also protecting the lighter from damage caused by incompatible fuels.