House Grail is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

How to Safely Dispose of Old Gas: What You Need to Know!

Gas Near Lawn Mower_shutterstock_Erica Allin

Gas Near Lawn Mower_shutterstock_Erica Allin

There’s lots of reasons to make sure that your lawn mower, generator, or other machinery gets emptied of fuel before long-term storage. If left inside for too long, the fuel could possibly go stale.

Gasoline in particular only takes about three to six months to go bad when unused. You will realize this when you go to fire the motor up for the first mow of the season, and nothing happens. The engine is lifeless.

So you’re stuck with some old gas. No problem! We have researched this issue and have solutions for you. This article will go through how to tell if gas has gone bad, how to dilute it (if you can), and how to safely get rid of it if you need to.

divider 1

Can’t I just dump it?

Gasoline Can
Image Credit By: bpcraddock, pixabay

No! There are several reasons why this is not a good idea.

For one, you might get fined. Gasoline detected in your septic system could leave you with a hefty price to pay, and it is dangerous for your home and your neighborhood.

Speaking of water, gasoline is not easy to filter out of water. Therefore, it’s bad for the environment around you that needs the water to survive and thrive.

A highly-combustible substance like gas needs to be disposed of with great care and attention, or disastrous fires could unintentionally ignite.

Disposal as a last resort: Try this first

Get a good look and smell

Is the gas really bad? Sometimes, seeing is believing.

Get the gas out of the tank to visually check it. First, find a spot that is well ventilated, as too much inhaled gasoline is bad for your health. Find a clear, disposable container to pour the old gas into. If you would like, you can pour some newer gas into another clear container to compare the two.

Gas that is too old, or stale, looks muddy or darker than it should. Normal gas is translucent. If you see rust or any particles floating in the gasoline, definitely get rid of it. These particles can break your fuel lines and clog your filter, causing bigger problems than you started out with.

Another way to tell if gas is stale is by its smell. Gasoline has a distinct smell loved by some and hated by others. Everybody knows the smell of gas. Old gas will have more of a sour smell to it and not seem like the normal gas smell. Again, we don’t want to be taking deep whiffs of this. You will know with a quick smell, then cap the container right away.

Dilution as a solution

pouring gasoline
Image Credit: RenineR, Shutterstock

Yes, you can dilute old gas with new gas! If you get the proportions right, the amount of the old gas added to the new gas will not affect the combustion needed to start your engine.

For a small piece of machinery with a small tank, like your lawn mower, topping off a half tank or less of old gas with new gas can get your motor going just fine for your yard work. After a while of using the machinery, you can stay on the safe side and add a little more fresh fuel to the tank to keep it going.

For a larger amount of old gas, you can dilute a certain amount of old gas straight into your car or truck. Follow these approximate dilution guidelines based on your vehicle’s gas tank size, using a proper gas can with a spout:

  • 9-gallon tank = at ¾ full, add ½ gallon of old gas
  • 12-gallon tank = at ¾ full, add ¾ gallon of old gas
  • 16-gallon tank = at nearly full, add 1 gallon of old gas

When you are diluting gas, or just trying to keep your gas fresh in the first place, fuel additives can be your friend. Ask your local auto service shop which fuel additives they recommend based on your situation.

Divider 2

Must dispose? Here’s how!

Safety first

Ventilation needs to be a priority here, so make sure your workspace is either outdoors or very well ventilated.

Prepare yourself for spills before they happen. Gasoline spills can lead to unexpected combustion, so clean up spills quickly with baking soda or kitty litter, then sweep it up after it has had time to absorb.

If it gets on clothing, use baking soda first to absorb the spill, brush it away, then follow with some liquid dish soap before laundering. Avoid machine drying until you are absolutely sure the gasoline is washed out.

Disposal best practices

Refuel Lawn Mower_shutterstock_Addrenn
Image Credit By: Addrenn, shutterstock

You will need a funnel and container. Make sure to put the gasoline in a proper, government-approved container. These typically look red and have a yellow spout coming out of them, and usually hold up to 5 gallons of gas, also called “gas cans” or “jerry cans”. They can be purchased at automotive parts stores, gas stations, and home improvement stores.

Carefully and slowly pour the old gas from the old container to the new one, or siphon it from your vehicle’s tank into the new gas can. The slower the better, as fast pours are likely to cause spills.

When you are transporting the old gas, you may choose to put the gas can in a larger plastic container so gas doesn’t spill inside your car. Drive carefully, and definitely don’t smoke while driving the gas around.

Places that take old gas

Here are three things you can do to find out who takes old gas in your area:

  • Start with a simple web search: “hazardous waste disposal center near me,” or try
  • Call your local waste services company.
  • Call your local fire department.

One of these options is sure to inform you on where to take your old gasoline for safe disposal.

divider 7


Can I let old gas evaporate?

It’s true that gasoline, when exposed to oxygen, evaporates over time. However, this is not a smart way to dispose of old gas. You must expose the gas to open air, which also exposes it to possible combustion. You could safely pour out a cup of gas at a time into a small container and watch it evaporate, but this is not practical, and leaving it unattended is unsafe.

Does AutoZone, or my local auto parts store, take old gas?

No, at least, it’s not likely. It is not cost-effective or practical for the automotive parts store to take your old gas for you. They do not have the means to recycle the gas.

divider 8


It’s best to keep gas fresh in the first place. Either completely empty a tank before storing for a long time, or add a fuel additive like a fuel stabilizer to keep the gas fresh for longer. Or, just use up the gas.

We know that life happens, gas tanks get forgotten and gas turns stale. Now you know what to do with that old gas. As you have read, it is really quite quick and easy to take it to a location that accepts old gas.

We hope your workshop is less cluttered with it, your machinery is working more smoothly, and you are much happier for getting rid of it!

Related Reads:

Featured Image Credit By: Erica Allin, shutterstock


Related posts

OUR categories

Project ideas

Hand & power tools