Before you store your lawnmower away for winter you'll need to empty the gas and refill the oil. These two steps will help the lawnmower last longer and save you time and money from maintenance when spring comes along. Remove any gasoline that is in the lawnmower by turning it on and allowing it to run outside until the gas is gone. When it comes to disposing the old oil, make sure to be eco-friendly and dispose of it at a gas station or service center. Then refill the oil to the correct level.