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Used cooking oil

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This is one of the big ones people should really stop doing. Though it’s not incredibly difficult for you to unclog cooled fat clumps out of your drain, you’re flushing the problem further down the line. It will all conceal and collect somewhere, clogging sewers and drains across the area. Keep some spare disposable containers on hand to limit mess.

Spent coffee grounds

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Coffee grounds can clog up like soil in your drains, which will cost you time and energy to unplug. They’re also great sources of nutrition, attracting all sorts of infestations from cockroaches to mice. Put that nutritional value to good use, compost it, or use the normal trash can and save yourself the hassle.


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Because they break apart into tiny pieces, some people assume that means they simply must go down the sink. This is unfortunately not the case, as they break down and become sticky – which is the opposite of how you want your drainage. They’re another great addition to the compost pile and make a good natural slug repellent.


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Super tough and fibrous veggies like asparagus are a pipes worst nightmare. They get shredded up on the journey and turn into organic headphone cables, tangled and tunneling in the drain. Not all organic produce is equally damaging, but these are the ones you want to make sure go to the right disposal.

Peach pits

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Anything you take great care to chew around you should probably avoid sticking in the disposal. Their hard and woody nature can potentially cause significant damage to your kit, but thankfully pits are easy to re-use. They hold a lot of fragrant chemicals, making them excellent for homemade air fresheners.

Feminine hygiene products

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Things happen, we all understand that. Everybody has been caught in a pinch where they can ditch something quick to avoid an awkward conversation, and that taboo is the real villain here. Obviously, they’re designed to be absorbent, they’re very fancy sponges, and nothing is disgusting about that being where all the other waste goes.

Kitty litter

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As fun as it is pulverizing rocks, kitty litter should be nowhere near a disposal unit. Depending on your refuse situation, you might sometimes be left with a few hefty little sacks of grit and waste come garbage day, and as annoying as that is you’re only causing more problems down the line by being lazy.


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Housework, and the tools you use for it, can take up an awful lot of space. Nobody wants to throw away those old paint cans, and when you finally summon the effort it can be tempting to just pour the problem away. There are a lot of chemicals in paint, though, both for the color and consistency, and they will wreak havoc on metal.

Chemical drain cleaners

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Not all cleaning products are made equal, either in quality or what goes into them. Not all drain cleaners will be compatible with all pipes, as many are made with different metals and plastics. These can react with cleaners and begin to corrode, which can cause leakage and warping.

Food peelings

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Any leftover scraps from cooking should be considered carefully before being disposed of. The hard stalks of vegetables like carrots and onions, and the fibrous skins of potatoes can all hold their own pretty well against a garbage disposal. Cooked foods have an easier time being mashed up, so boil your scraps to make stock before disposing.

Semolina flour

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This is an incredibly popular ingredient for baking and great reasons. It adds a wonderful texture and taste to anything from bread to pizza dough, and it’s great to stop dough from sticking to surfaces. It does expand a lot when introduced to water though, which makes it a no-go for any plumbing-based disposal.


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This goes for both cooked and raw rice, although raw is a lot more damaging. The grain can continue absorbing moisture long after it’s finished cooking, and only gets sticker as it does so. Instead of serving onigiri to the creepy crawlies, either dump it straight in the regular trash, but it can also be composted.


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Sex ed is on the fritz in America, so here is a free tip to avoid any catastrophic incidents. Latex can weaken when exposed to certain chemicals, mostly those found in oil-based lotions, but they’re pretty sturdy in water. They’re also designed to stop liquids from flowing through pipes, which goes against what plumbers fight for every single day.


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Medicine cabinet clutter is usually recyclable glass, cardboard, and plastic, but you shouldn’t dispose of unused products down the sink. This goes whether they’re in tablet or liquid form, as they’re both terrible for the environment and your pipes. Pharmacies usually have safe disposal bins for unwanted medication.

Plain flour

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Flour does go bad over time, so it’s a good idea to dispose of any that you’ve had in the pantry for a while. It’s not a good idea to use plumbing for that, as flour is just a very soft and delicious cement when it’s wet. It’s better to throw away the bag whole, and who has ever poured flour without it making a mess?

Animal bones

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The occasional smaller bit of gristle won’t immediately buckle the foundations of your house, but even cooked bones can be surprisingly tough. There’s a reason bones are ground down and not blended, as even after it’s broken, the jagged shards are still difficult to properly dispose of. Let nature do the job and use them for fertilizer.

Animal waste

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Even if the garbage disposal is the only option you have, it’s still best to sit tight and wait for another alternative. The bacteria will be aerosolized by its trip down, spreading all kinds of things you’d rather not have around your sink. It will also attract hordes of pests to your pipes, which can do as much damage as anything you pour down it.


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Be careful when washing any labeled fruit so that the sticker doesn’t find its way down the drain. On top of being, by nature, sticky, they can also hold together long enough to reach the ocean. Something about them is enticing the marine life, so we should avoid the issue altogether and peel them into the bin.


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Pouring milk down the sink has caused quite a stir in the UK, where the organic compounds in the waste make it’s way into water and lowers oxygen levels. This is bad for all kinds of reasons, as it affects the fish populations and throws the entire local ecosystem out of sync. The British government has warned against it in certain areas.


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The proper disposal method for fireworks (spent or dud) is soaking them overnight to ensure it’s deactivated. Some people perhaps heard soak and immediately thought of the sink, and then would happen if you put one in the disposal. It’s a bad idea, absolutely do not, just soak them.



Even in today’s digital day and age, it’s a good idea to carry a pen around. If you’ve ever been a fan of slim-fit pants with pens in the pockets (it’s a whole style) you know how annoying ink spillages are. The chemicals in pens aren’t too bad on the skin, but when released into the waterways they can cause a ton of damage.

Any medical waste

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Material wise this will comprise mostly of plastics, metals, and papers, none of which are good for your plumbing. They’ll shred the mechanisms and pipes, and you’ll be spreading whatever bacteria is on the into the air and waterways. Most test kits come with proper disposal information and are usually containers.


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The Italians have based their cuisine around things that shouldn’t go down garbage disposals. Onion, carrots, and celery form the bases of so many classic sauces and stews, and they’re all tough as nails to cram down a sink. Root veg tend to be more fibrous than fruit, which is a characteristic you want to avoid for disposals.

Lawn chemicals

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Chemical-based lawn fertilizers, herbicides, and pesticides should never be poured down the sink or idly thrown in the trash. These chemicals can have detrimental effects on wildlife and the ecosystem if you don’t take care when getting rid of them. There are usually designated refuse areas around department stores, or specialist waste facilities.

Anything containing asbestos

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We’ve all heard about the health risks posed by asbestos by now, but it can still catch you by surprise if you aren’t familiar with your house. You can remove asbestos yourself providing you take the necessary precautions, and one of those is knowing how to dispose of it. Double bagging will help prevent the spread of fibers.


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With how easy it is to shovel down, you would expect mayonnaise to have no problem getting down the drain. The trouble is, that mayonnaise is an emulsion of egg and oil, and adding water to that makes it separate. It’s going to clump up your drain like it does the McChicken, attracting vermin and causing blockage.

Anything claiming to be ‘flushable’

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Certain brands will claim their pet litter or wet wipes are flushable, and not only is that kind of a lie for the toilet, but it won’t do much good for the sink either. They can be flushed, but blockages can happen far past the U-bend. It doesn’t take many flushes to start noticing the effect, and your disposable will be much the same.

Paper towels

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Public bathrooms keep a bin near the paper towel dispenser because they know the human temptation to flush paper is strong. If they left it to us the streets would be flooded with cheap off-blue paper mache rivers, because they’re about as flushable as a fax machine. If you use these in your home, make sure they go in the bin.

Expired cosmetics

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While it may only happen once in a blue moon, a good make-up drawer clean-out can leave you with a few lotions and potions that need throwing out. You wouldn’t mix everything for a face mask, and something roughly similar happens when it mixes down the drain. The Fatbergs will look stunning though.

Chicken trimmings

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Some picky eaters (and children) get a little grossed out by raw meat. It’s common for them to want the white fat removed which usually comes with a little too much meat, but you’re babysitting so who cares? These fleshy, stringy fibers are a common source of drainage blocks and clogged disposer blades.


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Bathrooms feel purpose-built for you to shave over the sink. It’s such a tragedy then that hair is so awful for plumbing! Anybody who has lived with other adults will know the visceral disgust of having to pull a twisted, gnarly hairball out of the drain. Shaving onto a dry surface makes it much easier to sweep up hairs.


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The old rule comes back, if you struggle to chew something, your disposer blades are going to have a tough time cutting through it. Nuts are an excellent source of nutrition, but fiddling around with the shells is such a chore! If you can’t compost them, the next best thing is the normal trash, these things will attract hungry critters for sure.


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There is such a thing as too much oatmeal, even to its biggest (and oldest) advocates. It can be stored for a few days to eat at your leisure, but you should pour any excess. Starchy foods are one of the main culprits behind food blockages in pipes, so it’s best to use the normal disposal.


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A lot of amazing food comes in shells, and the scent it leaves is a good incentive to clear up. Crustaceans like crabs, lobsters, and shrimp can all be boiled with vegetables to make an incredible seafood stock, but even after that, it can damage your pipes. They’re similar to egg whites, becoming sticky and clumping easily.


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As another porous and absorbent food, you don’t want to throw your hypothetical sandwich leftovers into the sink. Not only are the most common toppings and spreads bad for drainage, but the bread itself is going to cushion all the other gunk that’s trapped in there. The easy solution is never to have leftover bread – what a great excuse to carb load!

Pumpkin pulp

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When it gets to that time of year, maybe spend a little extra to get a proper eating pumpkin. That way you can make use of basically the whole thing, and not have to worry about the bitter, pulpy, tendril-filled innards clogging up your kitchen. The seeds are also a no-go, but once again these are perfect for compost.


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Maybe it’s tamales night and everybody is too full with the food of the gods to clean, but this is a shortcut you don’t want to take. You would have to try pretty hard to eat a cornhusk, so your disposal unit is going to self-destruct before it’s finished a full rotation. Rodents do love to nibble on the fibrous fold though.



These are other foods that, while small and seemingly harmless, don’t respond well to being shredded. Their bodies are made of woody strands and a ton of water, which helps them grow fast and strong but also makes them absorbent. Even diced mushrooms can hold onto moisture, flooding your pipes with fungi.


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Pouring gravy down a sink is a low point in most people’s lives, made even worse by the fact you’re taking the sadness out on your plumbing. Thinner sauces like an au jus are fine provided they aren’t too fatty, but any sauce thickened with flour and butter and going to solidify into a solid gold brick down there.

Cigarette butts

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These are a nuisance to plumbers, as a little rain can wash a whole slew of them into a drainage duct. The mixture of paper and wet, carcinogenic spaghetti can form an impenetrable fortress in your waterworks. They’re also known to attract certain kinds of insects and rodents if they wind up pooling somewhere.