How To Dispose Of Cooking Oil And Other Substances

Last Update: January 11, 2024

After whipping up a fried treat like gluten-free coconut-flour fried chicken wings, there’s more left over than a killer snack—that oil-filled pan isn’t going to clean itself. Dumping it down the kitchen sink seems like the obvious answer, but don’t give in to temptation. So let’s talk about how to dispose of cooking oil.

Coconut oil and drain pipes don’t mix. At all.

Just look at any jar of refined or unrefined coconut oil and see how it solidifies at room temperature. So if it gets poured down the sink and travels through the drain and pipes . . . yep, it hardens, eventually causing tough blockages. You could instead, use your coconut oil to make a coconut oil candle. Problem solved!

So be careful pouring olive oil down the drain. You should understand how to dispose of cooking oil properly.

Lucky enough to have a garbage disposal? Well even that doesn’t just make any and all trash go poof. All kinds of food can accumulate down there and turn into a heaping mess of gunk.

Though clogged plumbing is certainly an inconvenience, it isn’t the worst thing about this scenario. Putting the wrong items down the drain can severely damage entire sewage systems. And worse—even though it goes through water treatment plants, many of these substances can end up in waterways, altering aquatic ecosystems, harming wildlife, and even contaminating our drinking water.

So what exactly is safe to send down the drain? If it’s liquid, non-hazardous, not viscous, and not extremely acidic nor alkaline, it’s usually fine. Other than that, here are a few items that should never, ever go down the drain or in the garbage disposal.

Can Olive Oil Go Down the Drain?

Olive oil is another common household oil that people often wonder about pouring down the drain. Like other oils, pouring olive oil down the drain can cause clogs and blockages in the pipes. When olive oil cools, it solidifies and can accumulate in the pipes over time, causing a buildup that can lead to clogs.

While olive oil is not as harmful to the environment as some other oils, it’s still important to avoid pouring it down the drain to prevent clogs and damage to plumbing systems. Instead of pouring olive oil down the drain, it’s best to dispose of it properly. One option is to collect the oil in a container and drop it off at a recycling center. Another option is to pour the oil into a sealable bag or container and throw it in the trash.

Why Should You Pour Salt Down Your Drain at Night?

Pouring salt down your drain at night is a popular household remedy for preventing clogs and odors. But what does it do?

The idea behind this method is that salt helps to break down any buildup or residue in the pipes and prevents grease and other substances from sticking to the inside of the pipes. Salt can also help to absorb any unpleasant odors that may be lingering in the drain.

To use this method, simply pour a few tablespoons of coarse salt down the drain at night before going to bed. Let it sit overnight, and in the morning, flush the drain with hot water to help wash away any residue or buildup that may have been loosened by the salt. It’s important to note that this method is not a substitute for regular drain maintenance and should only be used as a temporary solution to prevent clogs and odors.

While pouring salt down the drain can be effective, it’s important to avoid using too much salt, as it can corrode metal pipes over time. It’s also important to use coarse salt, as fine salt can dissolve too quickly and may not be as effective at breaking down buildup in the pipes.


Every year, up to 36,000 sewers overflow in the U.S., and about 47 percent of these are due to fat and oil buildups. Fats common in household oils—olive, canola, vegetable, butter, shortening, and even motor oils—break down into fatty acids that bind to calcium in sewers. These monstrous fat-calcium globs clog up sewage pipes. They’re called fatbergs. Enough said.

So, can you pour olive oil down the drain? We suggest against, it.

Instead of pouring this stuff down the sink, how should you dispose of cooking oil? You can collect oils in a container and drop them off at a recycling center. The next best option for cooking oil disposal is to take that container and throw it directly in the garbage. According to Rita Kampalath, Science and Policy Director for Heal the Bay, it’s actually better off in a landfill than in the sewers or waterways.


Although latex paint is water-based, it can still contain biocides that inhibit mildew, acrylics and vinyls, crystalline silica, and other additives that should not be poured down the drain. Absorb water-based paint with double the amount of clay cat litter and throw it in the garbage.

For oil-based paint, check with the State Department of Environmental Conservation or call the local city hall to find out about household waste collection day by neighborhood. Paint can also be recycled, so check with the aforementioned organizations about programs available locally.

Clean paint off of brushes and rollers safely by using a bucket of soapy water and a bucket of clean water to rinse, rather than a running faucet. Dispose of the buckets with local hazardous waste collections.

Coffee grinds

Coffee grinds can definitely clump up and end up clogging drains, especially if viscous liquids are regularly poured down there, too. There’s no need to send coffee grinds down the drain when they can be used for composting—they’re rich in nitrogen, which worms love.

Another use for coffee grounds: Add equal parts olive oil, grapeseed oil, or coconut oil to them and use the mixture as an antioxidant exfoliating scrub.

Vegetable bits

No matter how tiny, bits of vegetables like celery, rhubarb, asparagus, artichokes, chard, kale, lettuce, and potato peels should not be put in the garbage disposal. These fibrous or starchy vegetables can end up wrapping around the blade and cause a nasty clog that will be extremely difficult to clean out. Compost them instead.


Pasta and rice should also be left out of the garbage disposal, since water causes them to expand. They’ll just keep on soaking it up until they balloon into chunks that stay lodged in the garbage disposal. Grains can go in the compost.


Same deal with eggshells—they don’t belong in the garbage disposal. They are great for composting as well.

Medical waste

Never, ever put prescription drugs or other medical waste down the drain or toilet. Medicines and synthetic hormones have been detected in our waterways where they could be absorbed by aquatic wildlife, hindering their growth and reproductive health. “One of the most well-known effects is estrogen and similar chemicals altering female-to-male ratios in fish populations as well as being linked to more intersex fish—fish having both male and female characteristics,”  Kampalath said. “This is why drug take-back programs are so important. People should take advantage of these programs whenever they’re available.”

So, think twice before sending anything and everything down the sink. If a drain disaster does occur, go for some trusty baking soda and vinegar as a bailout.

Photo credit: Paul Delmont

Share this article

Dana Poblete

Dana's love for all creatures under the sun (bugs, too) drives her in her advocacy for ethical eating, environmental sustainability, and cruelty-free living. A natural born islander, she surfs when she can, and writes, always.

Download the app for easy shopping on the go

By providing your mobile number, you agree to receive marketing text messages from Thrive Market. Consent not a condition to purchase. Msg & data rates apply. Msg frequency varies. Reply HELP for help and STOP to cancel.

If you are visually-impaired and having difficulty with our website, call us at 1‑855‑997‑2315

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

© Thrive Market 2024 All rights reserved.