Interior Kitchen & Dining Appliances

15 Things You Should Never Put Down a Garbage Disposal

Master plumbers 'fess up to the foods that are most likely to clog your kitchen's pipes, and dull—or break—your disposal's blades.
Man uses kitchen sink faucet spray to wash vegetable peels toward kitchen drain.


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It might seem like it can handle anything, but feeding your garbage disposal the wrong items is a surefire recipe for bad smells, clogs and, ultimately, a broken appliance. While it’s fine to send most soft foods, ice cubes, chopped foods, and fruit peels through the garbage disposal, there are a few things that are better off in the trash can or your compost pile. We tapped master plumbers Roy Barnes and Hendrik Vandepoll, co-owners of Service Force Plumbing in Rockville, Maryland, for a few garbage disposal maintenance tips.

1. Fat, Grease, and Oil

Food frying in pan.

While your garbage disposal can handle liquid or semi-solid fat, grease, and cooking oil, the rest of your home’s plumbing system cannot. “The biggest no-no is grease,” Vandepoll says. “It may look harmless when it’s a warm liquid you can run through your disposal, but it will cool quickly in a dark, hidden pipe and become a sticky mess that can either create a blockage on its own or grab other debris as it passes through.”

According to Barnes, fats cause the same problems. “If you remove the excess fat off your pork roast, for example, and then grind it up in your disposal, you just created a greasy mess that can cause problems downstream,” he says.

“Grease should always be cooled in a container and then thrown in the trash. Some towns and cities even offer free caps that fit on soup cans so you can collect grease, cool it down, and put it right in the trash, can and all.”
— Hendrick Vandepoll, Master Plumber and Co-Owner of Service Force Plumbing in Rockville, MD

2. Pasta, Rice, and Oats

Boild spaghetti in a white colander, inside a white kitchen sink.

Delicious on your plate, but a problem in your plumbing, pasta, rice, and oats continue to swell with water, even after cooking. Toss them in the trash unless you’re willing to risk a clog.

3. Bones

Plate of eaten chicken bones.

Even though very small bones will probably pass through without a problem, it’s safest to keep all bones out of your garbage disposal. These hard items can break your disposal, or clog your plumbing.

4. Seafood Shells

Assorted seafood with lemon slice.

Like bones, seafood shells shouldn’t be ditched down the disposal. Whether it’s clams, oysters, mussels, or lobsters, these hard casings can damage the disposal’s blades or cause a clog.

5. Potato Peels

Potato peels.

It’s super convenient to peel spuds over the kitchen sink, but don’t send those peels down the drain. Potato peels turn into a gluey mass inside your plumbing pipes, and pose a major clog risk.

“Potatoes and potato peels being put down the drain are a big reason that the day after Thanksgiving is one of the busiest plumbing crisis days of the year, along with grease,” Barnes explains. “Your garbage disposal is great at turning starchy foods into a sticky mess that can either clog your pipes…or grab onto other debris as it passes through.”

6. Broken Glass or Metal

Hands sweeping broken glass into dustpan.

If metal or glass falls into your garbage disposal, don’t turn the appliance on. Instead, cut off power to the unit and switch off the disposal at the unit under the sink, then try to fish out the interloping item with a fork, grabber, or hook. If that’s not possible, put on gloves to protect your hands and carefully retrieve the item. Always make sure the garbage disposal is completely turned off before attempting to retrieve an item from the sink.

7. Eggshells

Many broken empty eggshells on wooden board.

There’s some dispute about whether or not eggshells are safe for the garbage disposal, but according to Barnes, they’re another big no-no. You’re better off composting them, crushing them up and mixing them into your garden soil, or disposing of them in the trash.

8. Chicken Skin

Close up of roasted chicken.

Removing skin before cooking chicken is sure to reduce your fat intake, but don’t toss the skin down your garbage disposal. It can easily clog your plumbing—and brings unnecessary germs and stink to your sink.

9. Fibrous Vegetables

Fresh green vegetables on wooden background.

While most vegetables can safely pass through the garbage disposal, fibrous veggies, including artichoke, celery, rhubarb, lettuce, kale, cornhusks, onion skins, asparagus, and chard tend to get tangled around the disposal’s blades. “These are actually hard on your garbage disposal itself and can shorten its lifespan,” Vandepoll says. Instead, deposit these veggies in your compost bin, or toss them in the trash.

10. Produce Stickers

Banana with produce sticker.

It’s fine to put citrus, apple, or banana peels into the garbage disposal, but be sure to remove any produce stickers before you do. Stickers are likely to adhere to the disposal’s blades, or the inside of your pipes.

11. Medication

Person getting pills from pill bottle.

Tossing unused medication down the garbage disposal might seem like a smart way to dispose of controlled substances, but putting drugs into your plumbing can negatively impact the water supply. Instead, the FDA recommends removing the drugs from their packaging, putting them in a plastic bag with an unappealing substance (think used kitty litter, or dog waste), then disposing of the bag in the trash.

12. Fruit Pits

Nectarine with view of fruit pit.

When you’re snacking on fruit and are left with just the pit, deposit it in your compost or garbage. While garbage disposals are generally pretty durable, this hard center seed will likely dent or break the blades.

13. Coffee Grounds

Removing used coffee grounds and filter.

Coffee grounds seem fairly innocuous when faced with the garbage disposal, but it’s actually one of the worst things you could put down the drain. Eventually the grounds build up and form a sludge (like the dregs in your coffee pot), which creates a clog. Instead of tossing them into the trash, add coffee grounds to your garden soil or compost bin.

14. Sauerkraut

Sauerkraut in jar.

Be careful when you’re scraping plates after a barbecue! Sauerkraut is a delicious condiment, but it’s also a prime offender for clogging a garbage disposal. Like potato skins, sauerkraut will form a gelatinous goo in the drain.

15. Nuts

Glass bowl of mixed nuts.

They might be small, but nuts spell disaster when they meet with a garbage disposal. Think about it: The garbage disposal’s grinding and mashing actions are similar to those for making nut butter. This pasty concoction won’t do your hardworking appliance any favors.