Down the drain? Does it depend on the type? With bacon fat, I usually let it solidify in a cup lined with foil, and then throw it out. With used canola oil, I'm not quite sure what to do because it doesn't solidify.

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    I'm voting to close this question because this primarily depends on the location of the OP. In Belgium, we have collection points specifically for used fats.
    – Mien
    Commented Apr 10, 2015 at 11:48
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    @Mein It wouldn't make sense to give advice for each country, but an answer could be written suggesting people check to see if collection points are available in their country citing Belgium as an example. Commented Apr 10, 2015 at 20:24
  • Not just dependent on location, but on volume of waste oil and residential vs commercial status... Commented Nov 11, 2015 at 10:11

14 Answers 14


Never down the drain. We've had a few incidents in my neighborhood where the sewer pipes were clogged with fat, and a few people's basements flooded with sewage as a result.

For fats that solidify, let them do so, then pitch them in your regular garbage. Chill grease in the fridge if you need to get it to harden up. For ones that don't solidify, pour them into a sealable (hopefully non-recyclable) bottle, and throw the whole container away with your regular garbage.

It's possible that your area might accept cooking fats & oils as part of a recycling effort. Ours does for motor oil (I live in Maryland).

For restaurants, some places (eg, the state of Maryland) require a system for catching grease that's been washed down the sink. It's my understanding that they're fairly expensive (a couple thousand dollars US), but the fines for not having one installed may be even more, and they won't let new restaurants open without one.

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    The water and sewer guys refer to the resultant fat clogs as "Grease Logs" and, indeed, it's an accurate description. Better to just throw that junk off the back porch. Commented Jul 30, 2010 at 1:28
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    @Adam Shiemke: Yea, it doesn't degrade. The guy who comes up with an enzime that eats fat will make a mint cleaning arteries and drains. Commented Jul 30, 2010 at 2:00
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    @Satanicpuppy: That guy with the fat-eating-enzime had better hold the movie rights, it'll be sure to be picked up by some bacteria and decimate the human race :) Commented Jul 30, 2010 at 11:09
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    A fat-trap is not really expensive. It's just a place where water & fat slow down so the fat can float. The water escapes at a lower level. Commented Apr 18, 2014 at 11:49
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    Wonder if oil can ever revert to the kind of grease that causes clogs if you mix it with plenty of detergent (eg pouring a cup of dish soap and a cup of water into a pot of oil and stirring before pouring it away)? Commented Nov 11, 2015 at 10:30

Composting used oil can be done. Since it is organic it makes great earthworm food. But as Joe mentions: be careful to make sure you're doing it right. Large quantities of oil used to cook meat can attract vermin to your compost, and lots of oil in your compost can form hydrophobic barriers, reducing water & airflow.

Perhaps a safer option: After allowing used oil to cool you should put it in a small sealed container and throw it out with the trash. You can save empty jars for this purpose. If you produce large amounts of oil you may need to take it directly to your landfill, oil recycling station, or ask a local restaurant if you can drop off your oil there.

I advise against pouring it down the drain. It will clog overtime.

Also, you can reuse most oil several times. Deep-frying oil can be filtered and reused 3-4 times (more depending on the quality and your comfort). Bacon fat can also be filtered and then stored in your refrigerator.

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    I had always been told to avoid oil in compost, but after you mentioned it, I looked into it, and it looks like it's possible, but might cause problems if you don't do it right : compostthis.co.uk/item/cooking-oil ; and cause problems if it is done right : cityorganicgardener.blogspot.com/2006/12/…
    – Joe
    Commented Jul 29, 2010 at 22:13
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    When I had a slow compost pile I never had a problem with throwing oil in it occasionally. I don't frequently deep fry so that might be why.
    – hobodave
    Commented Jul 29, 2010 at 22:31
  • I was told not to reuse oil more than twice.
    – Sruly
    Commented Jul 29, 2010 at 23:52
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    @Sruly: You can follow that advice if you like. If you eat deep fried food in a restaurant chances are it's been fried in reused oil. This specific topic was covered here: cooking.stackexchange.com/questions/3014/frying-oil-reuse
    – hobodave
    Commented Jul 30, 2010 at 0:43
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    Here are some good guidelines for reusing oil (or not) from Columbia University. Commented Oct 26, 2012 at 0:46

You can mix fats together that will harden and keep them. Once you have enough, mix them with some nuts and seeds and you have some home made fat balls for bird feeding.

  • This is a good idea. Keep a tin can next to the sink, pour any oils and fats into it. When its full, pop a load of nuts in, and put it in the garden. If its solid you should be able to pop it open.
    – NBenatar
    Commented May 2, 2014 at 16:29
  • It's better to feed worms - that will feed birds and other animals I believe
    – vstepaniuk
    Commented Oct 14, 2022 at 12:09

Unless you fry very often, you can store the twice/thrice/whatever used oil and use to saute or as an ingredient in cakes and breads that call for oil. You need to keep track a bit, since you don't want to put the oil used to fry shrimp into cookies, but it might work well to saute onions for shrimp tiki masala.

Bacon grease can likewise be reused. Its my personal favorite for frying onions used in heavy curries from northern India and hearty meat dishes like stews. Simply dump into an old can or a pyrex container, cover in cling film or foil, and store in the fridge for a week or two (it can pick up odors, so not too long), or freeze in cubes for future cooking (would probably keep a year or so).

Other fats can be put to good use: chicken fat is used as a condiment in Central European Jewish food, for instance.

If you do fry a lot, you can save the used oil and make biodiesel. The process if fairly simple if you have a few days to let the product sit.

  • Good point -- I save my bacon grease, but I've been cutting back on the bacon so I don't have it as often as I used to. I use it to cook pancakes & french toast and other things I'd serve with bacon anyway.
    – Joe
    Commented Jul 30, 2010 at 2:09
  • Bacon grease makes a wonderful substitute for butter in savory corn bread as well.
    – Shog9
    Commented Apr 30, 2014 at 18:47

You can always pour old oil back into the empty oil bottle (or any bottle or jar) and throw it in the regular trash.


When I have some spare in a pan after a bit of a fry up or whatever I get the end pieces of bread from the current loaf and pour the fat all over them, then I let it soak in and then dry up for a bit and I put that out for the birds.. They love it - There's a wood pigeon here that loves bread with bacon fat!


Bacon grease can be a real pain in the ass. Pour it while it's liquid and hot into an empty plastic bottle and you risk burning yourself or burning a hole in the container. Wait for the grease to dry in the pan and you've got a hell of a clean up job on your hands. No matter what, leaving bacon grease to sit in your home will cause a stink. Not sure about you, but I don't like to think about or smell bacon very long after I've eaten it. So what to do?

Unfortunately, there doesn't seem to be a silver bullet out there. Many recommend pouring grease into a non-warpable container like a Chinese takeout box or a milk carton, but not everyone has something like that laying around.

An option I've found useful: line a glass or mug with aluminum foil and pour hot grease in there. To speed up solidification, put the ensemble in your freezer for a few minutes, then pull it out, and trash the grease-foil -- preferably in a bin outside.

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    Bacon grease is a highly flavorsome thing to fry stuff up in. It's the one oil I reserve a special glass cup for, and use rather than toss. Commented Apr 10, 2015 at 12:21

Some utilities have or are starting residential cooking oil recycling programs. They will either have a drum to pour oil into, or a cabinet to drop off a bottle. If there is no program in your area, the trash can is the best option.

You should never dump oil down the drain, as it can cause odours and back-ups in your home and the sanitary sewer collection system.

You can learn about the program in Hillsborough County, Florida by visiting: www.hillsboroughcounty.org/core

  • Great answer, keep them coming. FYI--The link or chain which is located just to the right of the italicize "I" at the top of the answer box is how you add a link to a website, I provided this for you.
    – Chef_Code
    Commented Apr 10, 2015 at 6:57

Many restaurants have collection containers in back and will accept your fats while those using biodiesel may pull their vehicle up and fill up for free!

It depends on the area, but I have heard of people going across the country on restaurant freebies! Check it out some more, to see if this is viable in your area.

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    At least in the US, this fat is often sold for recycling, and is unlikely to be given away for free.
    – SAJ14SAJ
    Commented Mar 7, 2014 at 14:09

I don't deep-fry so I never have multiple quarts of used oils. For a skillet full of used oil with too much crumb in it to reuse, I use a lot of Dawn and very hot water to fully emulsify the fat and then wash it down the drain with hottest water. I'm on a septic tank in the country for nearly 20 years with no problems.

I save bacon fat that isn't overheated to fry tortillas and veggies headed for a stew or stir-fry. I keep bacon-fat in the fridge, although many southern cooks just keep it in a pot by their stove.


fats and grease are not compostable, that much i know. not sure what else you can do with it. my grandmother used to just pour it into a can, freeze it, and toss it in the garbage on garbage day.

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    Anything that used to be alive is compostable. Different things take different lengths of time to compost, that's all -- and some things attract vermin.
    – slim
    Commented Jul 9, 2013 at 10:51

Get a funnel and pour it into an old milk gallon or some other used container with a screw on cap. Then just toss it into the trash bin. No chilling, no clogged plumbing, no mess (if you're careful).


There are now (2018) plenty people using old chip oil for bio-fuel in their old diesel cars. Do a few web-searches for "waste vegetable oil recycling" "wvo recycling" "used chip oil collection" etc. and you might find someone local to your neighborhood who will arrange to collect it for free. I do this in Grimsby U.K. along with many others.


In my area (Vancouver, Wa), the recyclers will take used engine oil, but NOT used cooking oils! If I'm desperately trying to do the perfectly right thing, a couple of the local restaurants will let me dispose of my oil in their collection containers, but that's a pain in the A** So for the past 20+ years, I've simply mixed a couple of tbsp of dish detergent (that's enough for 1/2 gal of oil) into the oil and then slowly drizzled it down the drain w/plenty of Hot water. There has Never been an incident with the sewers in my neighborhood!

  • Voted that one up because that technique might or might not be OK for small amounts - if somebody know it is not, it would be great if that person could comment on the reasons. Commented Nov 11, 2015 at 10:59

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