Old Gas in Your Garage? Here’s How You Can Use It

Trying to get rid of old gasoline can be a hassle, especially if you’ve let it gather for a few seasons and now have quite a few gallons laying around. The good news is there may be a useful way for you to repurpose that old gas that’s lying around!

Getting rid of old gasoline can be a problem. Here are 6 ways to use old gasoline:

  • Pour it on Weeds to Kill Them
  • Use it to Burn Brush
  • Use it to Kill Ants
  • Reuse it in an Old Work Tractor
  • Mix it With Oil to Burn in a Waste Oil Heater
  • Gradually Mix it With New Gas

How to Reuse Old Gas

Most of us end up with old gas sitting around in the garage or leftover in a lawnmower or snowblower at the end of the season. This leaves us trying to figure out how to make old gas usable.

I’ve come up with 6 ways to reuse old gas that take an otherwise worthless product and make it useful again. Before we get into those ideas, you need to keep in mind that gasoline is very flammable and using it in any way other than it’s intended to be used can result in injuries or fines.

Pour it on Weeds – Old gasoline is amazing at killing off weeds. You just need to make sure that you don’t want anything else to grow in that area. After you pour gas onto the ground, you’re not going to be able to grow anything in that spot for a long time.

It works best to keep grass and weeds from growing through the cracks in pavement, driveways, and sidewalks.

Use it to Burn Brush – Burning brush is something that has to be done from time to time, especially if you live out in the middle of nowhere. Gas can make getting wet or freshly cut brush to burn much easier.

Just be really careful and don’t use a lot of gas. Older gasoline doesn’t evaporate quite as fast as new gasoline but it still puts off flammable fumes and lighting it can be dangerous!

Use it to Kill Ants – If you live in an area that has fire ants, then you know how hard it can be to get rid of them! Most of the different granules and poisons can be hit and miss but old gas can make short work of them!

Just pouring some old gas into the fire ant mound should kill them off. I don’t recommend trying to light it, but some people seem to have good luck burning it after they pour in it in. In my opinion, the gas alone is enough to kill them off.

Reuse it in an Old Work Tractor – Some old work tractors are notorious for running on just about anything that you pour in them. If you’re lucky enough to have one hanging around, then they’re a great candidate for your old gas.

If you have a newer tractor then you may want to mix it with new gas before you pour it into the tank.

Gradually Mix it With New Gas – One of the best ways to use old gas is to mix it with new gas. Adding a little old gas with your new gas should make it usable in most engines.

I do this all the time for gas that I use in my lawnmowers, snowblowers, and for any gas-oil mixtures, I have. Smaller engines seem to use older gas mixed this way with no problems.

Some people recommend pouring a little old gas into your car after you fill-up. I’d stay away from that unless you really need to do it…stick to using it in small engines and you should be fine.

Mix it With Oil to Burn in a Waste Oil Heater – Waste oil heaters use old oil that can’t be used for its intended purpose anymore and burns it to produce heat.

Adding a little old gas to the mix of waste oil allows you to burn the old gas as a heat source on top of your old oil. Waste oil heaters are great for garages or as an emergency heat source. Just make sure you check the legalities in your area because some places place healthy fines on people burning waste oil without a permit.

Does Gas Go Bad?

Gas can obviously become old and not as good as it was when it’s new, but does gas ever go bad? The answer is yes.

The difference between old and contaminated gas is something that you should be able to recognize before you put gas that you’re unsure of into an engine. Old gas can be mixed with new gas and added to an engine with little worry about damaging the fuel system. Contaminated gas can easily damage the fuel system and should be reused in ways that don’t involve burning it in an engine or properly disposed of.

Old gas loses efficiency and its ability to ignite inside an engine as the flammable components evaporate away or through exposure to oxygen. In this case, the gas is just old and not contaminated.

Gas gets contaminated when water is absorbed into it or it separates into separate gasoline and ethanol layers. Most gas sold in the U.S. is mixed with Ethanol which has a tendency to attract water from humidity in the air.

Old gas will appear slightly darker or have a sour smell to it.

Bad gas will be separated into layers, be much darker than it originally was, or have sediment in the bottom of the container.

How Long Does Gas Last?

Gas loses its efficiency as it ages. The length of time that gas is “good” for depends on how it’s stored and the type of gas.

The best way to keep gas from going bad is to keep is in an approved container that keeps air out. This prevents the gas from oxidizing, prevents some of the more volatile components from evaporating and it helps reduce the amount of water that can get absorbed into the fuel from the humidity.

Gasoline with ethanol added to it (the majority of gas sold in the U.S.) doesn’t last as long as gas that doesn’t last as long as gas without ethanol added. This is because the ethanol attracts moisture from the air and contaminates the fuel with water. Ethanol added gasoline lasts around three months before it begins to lose its potency.

Gasoline without ethanol can still be found if you look around in your area. Gas naturally repels water which helps it stay good for longer periods of time. Gas without ethanol will usually last six months before it loses its potency.

You can drastically increase the length of time that your gas is good for by adding a fuel additive like STA-BIL to your gas. The length of time varies by manufacturer but you can expect to get 1 – 3 years of life out of gas with a fuel additive added to it!

Best Way to Get Rid of Old Gasoline

There are many good (and legal) ways to get rid of your gasoline. If you’re worried about the danger or legalities of other ways of disposing of gasoline, you should use one of these methods to get rid of your old or contaminated gas.

Contact Your Local City Government – Many cities have recycling facilities or hazardous waste drop off centers that you can bring old gas to. They will repurpose the gas or dispose of it properly. Always call in advance as they can have limited hours or limits on the amount of gas that you can drop off at one time.

Use Private Disposal Services – There are private companies that will take your hazardous waste for a fee. I’d suggest calling around a little if there is more than one option for this service in your area because they can be expensive.

Attend a Community Collection Event – Some areas have events where you can drop off hazardous materials like old gas off. This helps get contaminates out of the community and to proper disposal sites.

Contact Local Automotive Stores – Some auto parts stores have collection facilities for used oil and gas. These services are normally free so call around for one that will take your old gas.

Call Your Local Fire Department – Sometimes your local fire department can dispose of old gasoline for you. At a minimum, they should be able to get you the number of a place that can help.

Related Questions

Can you dump old gas on the ground? Gasoline is a hazardous material and should not be poured on the ground. You should always bring it to the proper facility to dispose of it or recycle it properly.

Does gasoline evaporate? Gasoline evaporates much faster than other liquids. This is because it has weak intermolecular attractions. The speed that gasoline evaporates depends on the temperature, the higher the temperature, the quicker it will evaporate.


Getting rid of old gasoline can be annoying and it often leads to people letting it gather until they absolutely have to do something about it. The good thing is there are quite a few useful ways to put that old gas to use.

Leave a Comment

Your email address will not be published. Required fields are marked *