How to dispose of CO2 cartridges depends on two things: whether the container is meant to be thrown away after one use, and whether it is truly empty. The little 12 and 16 gram cartridges used in airguns, bike tire inflators and life jacket rearm kits are single-use steel. The cylinders in a soda maker, a paintball marker or a kegerator are refillable and should go back into the refill system. Either way, carbon dioxide is stored under high pressure, so a cartridge or tank that still holds gas does not belong in a trash can or a recycling cart. This guide explains how to tell what you have, how to make sure it is empty without taking risks, and where each kind should go.
The quick answer
- Small single-use cartridges: use them up in the device they were made for. Then take them to household hazardous waste, or to a scrap metal or recycling site that says it accepts fully discharged cartridges. Do not put them in the curbside cart unless your program's list names them.
- Full or partly used cartridges you no longer need: give them to someone who uses them, or take them to household hazardous waste.
- Soda maker cylinders: exchange or return them through the brand's program instead of throwing them away.
- Paintball and airgun tanks: refill them at a paintball or airgun shop; ask the shop what to do with a tank that is past its test date.
- Large cylinders: return them to the gas supplier you got them from. Many are owned by the supplier, not the user.
Which kind of CO2 container do you have?
- Disposable cartridges. Small, bullet-shaped steel cartridges, usually 8 to 16 grams, plus larger single-use sizes for some airguns. They have a thin seal that the device pierces. Once pierced they cannot be refilled. Whipped cream chargers look similar but hold nitrous oxide; they are handled the same way once empty.
- Soda maker cylinders. Aluminum or steel cylinders with a brass valve, sold through an exchange system.
- Paintball and airgun tanks. Refillable aluminum tanks, commonly a few ounces to a couple of pounds of CO2, with a pin valve on top.
- Large cylinders. 5, 10, 20 pound and bigger tanks used for draft beer, home brewing, aquariums, welding gas mixes and some fire suppression. These are pressure cylinders with their own valve and a stamped test date.
Make sure it is empty, the safe way
The safest way to empty a CO2 container is to use it for its normal job. Fire the airgun, inflate a tire or run the soda maker until no more gas comes out, working outdoors or in a well-aired space. A cartridge that has been pierced and no longer hisses when the device is triggered is usually spent. If you are not sure, treat it as full.
Do not try to empty a cartridge or tank by drilling, cutting, hammering or heating it, and do not loosen a valve on a cylinder that still holds pressure. CO2 can push a fitting or a shard out with real force, and the gas can build up in a small room because it is heavier than air.
Small disposable cartridges
Rules for spent cartridges vary more than most items. Some cities tell residents to bring every CO2 cartridge to household hazardous waste, empty or not, because sorting crews cannot tell a spent one from a full one. Other programs and many scrap yards accept fully discharged steel cartridges with other scrap metal. Before you go:
- Check your local list. Search your city or county's recycling guide for "CO2 cartridge" or "compressed gas."
- Call the scrap yard or recycling site and ask whether it takes spent cartridges and how it wants them packed.
- If neither says yes, take them to a household hazardous waste drop-off or collection day. Not sure what else counts? See what counts as household hazardous waste.
- Keep unused ones in use. A box of unopened cartridges is worth something to a cyclist, airgun owner or paintball player, so offering them to a friend or a club is often the easiest answer.
Life jacket rearm kits are a special case. After an inflatable life jacket fires, the spent cartridge comes out and the kit replaces it. Handle the old one like any other spent cartridge, and follow the jacket maker's instructions for rearming.
Soda maker cylinders
Soda maker cylinders are built to be refilled many times. Brands run exchange programs where you hand in an empty cylinder at a participating store or by mail and pay for the gas in a full one. The returned cylinders are inspected, refilled and eventually retired by the company. If you have stopped using the machine, look for the brand's return option instead of putting the cylinder in the trash or a scrap bin. A household hazardous waste site is the fallback if no return option is available near you.
Paintball and airgun tanks
Refillable paintball and airgun tanks are pressure cylinders that must be retested on a schedule, and the last test date is stamped on the tank or neck. A shop will refill a tank that is in date. Once a tank is out of date, it cannot be refilled until it passes a new test. Your options are to have it retested, trade it in where a shop offers that, or ask the shop to empty it and remove the valve so it can be scrapped. Many scrap yards will only take a cylinder with the valve removed, and taking a valve off is a job for someone with the right tools.
Large CO2 cylinders
Large CO2 tanks for draft beer, brewing, aquariums or welding are usually filled or swapped by a gas supplier, welding supply store or beverage gas dealer. Many of these cylinders are owned or leased by the supplier, and the ownership is often stamped on the collar. Return it to that supplier, even if you no longer have an account. If you own the tank outright, a gas dealer may swap it, buy it or take it for disposal. The same logic applies to other gas cylinders; see our guides on oxygen tanks, returning a helium tank and propane tanks.
What not to do
- Do not put charged cartridges or cylinders in trash or recycling. Trucks and sorting machines crush loads, and a pressurized container can burst.
- Do not puncture, cut or heat them to empty them.
- Do not burn them or toss them in a fire pit.
- Do not leave them in a hot car or in direct sun. Pressure inside rises with temperature.
- Do not mix them into a bag of aerosol cans or propane canisters without asking the drop-off site first. Our guides to aerosol cans and butane canisters cover those items.
Storing them until you can drop them off
- Keep cartridges in their box or a sturdy container, in a cool, dry place out of reach of children.
- Store tanks upright and secured so they cannot fall, with the valve closed and any cap in place.
- Keep spent and unused cartridges apart and label the container so nobody has to guess.
- When you drive them to a drop-off, keep them in the trunk or bed, secured, and do not leave them in a parked car.
CO2 cartridge disposal FAQ
Can I throw CO2 cartridges in the trash?
Not if they hold any gas. Charged cartridges can burst when a truck compacts a load. Many places want even spent ones taken to household hazardous waste, so check your local rules before you toss one.
Are empty CO2 cartridges recyclable?
Often, as scrap steel, but only once fully discharged and only where the program or scrap yard says it accepts them. Ask first, since some cities send every CO2 cartridge to hazardous waste.
How do I know a CO2 cartridge is empty?
Use it in the device it was made for, outdoors, until no more gas comes out when you trigger it. A pierced cartridge that no longer hisses is usually spent. If you are unsure, treat it as full.
Should I puncture a CO2 cartridge to empty it?
No. Drilling, cutting or heating a cartridge that still holds pressure can throw metal and release gas fast. Empty it through the device or take it to household hazardous waste as is.
What do I do with an old SodaStream cylinder?
Exchange or return it through the brand's program at a participating store or by mail. The cylinders are refilled and eventually retired by the company, so they should not go in trash or scrap.
Where do I take an expired paintball CO2 tank?
Ask a paintball or airgun shop. An out-of-date tank cannot be refilled until it passes a new test, so the shop can retest it, take it in trade, or empty it and remove the valve so it can be scrapped.
The bottom line
Use a CO2 cartridge or tank for its normal job until it is empty, and never puncture or heat it to speed things up. Spent single-use cartridges go to household hazardous waste or to a scrap or recycling site that says it takes them. Refillable cylinders, from soda makers to paintball tanks and beverage gas, should go back to the brand, the shop or the gas supplier. When in doubt, call your local hazardous waste program before you haul.