Many people may find themselves with old gasoline after leaving a gas can unused for several months. When this happens, it is important to know how to identify and properly dispose of the fuel.
Gasoline generally lasts about six months in a container before it starts to oxidize and lose its effectiveness. Signs that gasoline has gone bad include a change in smell, discoloration, debris, or the presence of water. Using a gasoline stabilizer can help extend its shelf life up to 12 months.
When disposing of bad gasoline, experts recommend transferring it into a government-approved container and contacting local waste management services for approved disposal sites. “The proper way to dispose of gasoline is as simple as a few simple steps: Put the gasoline in a government approved container, Find a local disposal site by calling your county or city waste management, Dispose of the bad gasoline at an approved disposal site.”
Some alternative methods exist but come with risks or legal concerns. Mixing small amounts of bad gasoline with good fuel for use in cars or small engines is sometimes possible if there is no water or debris present. Cars are generally better equipped than small engines to handle mixed fuel.
Other methods—such as using old gasoline as weed killer or letting it evaporate—are discouraged due to environmental hazards and potential legal issues. The guide notes: “While this may be effective, it is certainly frowned upon, if not outright illegal.” It suggests considering eco-friendly alternatives like weed-killing torches instead.
If bad gasoline has already been added to an engine, recommended steps include draining both the tank and carburetor, cleaning out any residue with good gas or rubbing alcohol, then refilling with fresh fuel. Adding rubbing alcohol can help address any remaining water and improve ignition.
The guide stresses compliance with local regulations when disposing of expired fuel and encourages environmentally responsible practices rather than unsafe shortcuts.
