If the butane can still have a lot of gas, it is best to use it up as soon as possible. Make sure to use it in a well-ventilated area, away from any open flames or sparks, as the gas is flammable. Additionally, make sure to turn off the gas valve and disconnect the gas hose before attempting to use the gas. Once the gas is used up, dispose of the can safely and responsibly. If the can is empty, you can recycle it.