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What should you never put down a garbage disposal?

Never grease, fat or oil, hot liquids, clam or oyster shells, glass, china, plastic, metal, caustic drain cleaners, paint, solvents or other chemicals. Go easy on fibrous scraps like corn husks and celery, big batches of peels and large amounts of eggshells. On a septic system, Virginia's health department advises limiting or skipping the disposal altogether.

Free to ask. Local shops send quotes, and you pay only when you book one.

By Kasra Taheri, Founder, LoclisPublished

Researched and drafted with AI, then checked claim by claim against the sources listed below before it was published. Prices and rules change; the dates beside each source say when it was last checked.

Step by step

Read when to stop and call a pro, further down this page, before you start.

  1. Step 1: Scrape plates into the trash

    Scrape food scraps from plates into the garbage first and use the disposal for what is left.[3]

  2. Step 2: Can the grease

    Pour cooled grease and oil into a can or jar and put it in the trash, and wipe greasy pans with a paper towel before washing.[4]

  3. Step 3: Start the cold water first

    Turn on the cold water, then the disposal, before any food goes in.[1]

  4. Step 4: Feed scraps gradually

    Add peels and scraps a little at a time with the water and disposal running, rather than packing the chamber.[1]

  5. Step 5: Grind until it is quiet

    Keep it running until you hear only the motor and water, then let cold water run for several seconds to flush the drain line.[1]

  6. Step 6: Keep the stopper in

    Leave the stopper in the sink opening when the disposal is not in use, so spoons and bottle caps cannot fall in.[1]

  7. Step 7: Freshen it now and then

    Every so often, grind ice cubes with lemon or lime wedges under a medium stream of cold water.[2]

The short list of never-evers is grease, fat and oil, anything that is not food, and harsh chemicals. A disposal grinds soft food waste into small particles; it is not a trash can. The longer list is food that is hard on the unit or your pipes, and in parts of Virginia, especially on septic, the advice is to use the disposal sparingly or not at all.

Looking down into a garbage disposal's grinding chamber, with its round plate, two metal lugs and the toothed grind ring around the edge
Flammingo, Public domain, via Wikimedia Commons

Never put these in a disposal

InSinkErator is specific about what never goes in: "Do not put the following into a disposer: clam or oyster shells, caustic drain cleaners or similar products, glass, china, or plastic, metal (such as bottle caps, steel shot, tin cans, or utensils), hot grease or other hot liquids."[1] It adds: "Do not dispose of the following in the disposer: paints, solvents, household cleaners and chemicals, automotive fluids, plastic wrap."[1]

The rule underneath is simple. InSinkErator says the unit is designed for normal household food waste, and that putting anything else in it could cause injury or property damage.[1] Paper towels, napkins, twist ties, rubber bands, fruit stickers and cigarette butts all go in the trash.

Grease, fat and oil

Grease is the one to take most seriously, because the damage happens out of sight. InSinkErator tells owners not to pour grease or fat down the disposer or any drain, because it can build up in pipes and cause blockages, and to put it in a jar or can in the trash instead.[1] The King George County Service Authority puts it plainly: "When mixed in small amounts with hot water, F.O.G. flows easily. But once it cools, it hardens inside pipes."[3] It warns that when those blockages build up, "Sewage may overflow into your yard or even back up into your house or business."[3]

It includes the less obvious ones: EPA's septic guidance counts fats, butter, wax, cheese and heavy cream as grease,[9] and the oil left in a pan counts too. Pour cooled grease into a can, wipe the pan with a paper towel, and put both in the trash.

Food that is hard on a disposal

Some food is not dangerous but can clog the disposal or the drain below it.

  • Fibrous and stringy scraps. InSinkErator says: "Don't grind large amounts of egg shells or fibrous materials like corn husks, artichokes, etc., to avoid possible drain blockage."[1] InSinkErator adds that Standard Series models handle any food except stringy, fibrous scraps such as banana peel, celery and rhubarb.[2] The maker says its Quiet Series can grind most food waste,[2] so check your own model's manual.
  • Big batches of peels. "Don't fill disposer with a lot of vegetable peels all at once."[1] Feed them in gradually with the water and disposal running.
  • Hot water while grinding. InSinkErator says not to use hot water while grinding, though draining hot water between grinding is fine.[1]

Some hard things are fine. InSinkErator lists small bones, fruit pits and ice as things to grind, because the hard particles scour the inside of the grind chamber.[1] Large bones are another matter; put them in the trash.

What Virginia sewer utilities ask

Several Virginia utilities ask residents to use disposals less, because of what reaches their sewer lines.

  • City of Salem: "Use garbage disposals sparingly or not at all."[5] It adds: "If your disposal is used make sure you flush the sewer lines thoroughly."[5]
  • City of Alexandria: "Minimize use of garbage disposals as many foods are cooked or contain additional oils."[4] And: "Use strainers on sinks to catch food scraps and dispose of in the trash."[4]
  • King George County Service Authority: "Avoid using your garbage disposal whenever possible."[3]

Check your own utility's website for its fats, oils and grease guidance.

If your home is on septic

On a septic system, the advice is firmer. Virginia Cooperative Extension says that if you have a septic system, "use of garbage disposal units should be kept to a minimum or preferably not be used at all."[6] Its reason: "Waste from garbage disposal units accelerates the accumulation of solids in the septic tank."[6] The Virginia Department of Health tells septic owners to eliminate or limit the use of a garbage disposal to cut the fats, grease and solids that reach the system and could clog the drainfield.[7]

EPA says that if you must use a garbage disposal on septic, your tank will need to be pumped more frequently.[9] EPA also lists coffee grounds among the things not to pour down the drain into a septic system.[9] There is more on looking after a system in how to keep a septic system in good shape between inspections.

If something does go down

Do not put your fingers or hands into a disposal.[1] If the motor stops mid-grind, it may be jammed. InSinkErator says to turn the power off, work the Jam-Buster wrench back and forth in the hole in the center of the bottom of the unit until it turns a full revolution, take the object out with tongs, let the motor cool for 3 to 5 minutes, then press the red reset button on the bottom.[1] If it still will not run, check for a tripped breaker or blown fuse.[1]

One more rule from the same manual: it says not to use the sink with the disposal for anything other than food preparation, such as bathing a baby or washing hair.[1]

Stop and call a pro if

  • The disposal hums but will not turn after you have cleared the jam and pressed reset, or it trips the breaker every time.
  • Something metal or glass is stuck and tongs will not reach it.
  • Water backs up into the other sink bowl or the dishwasher. The clog is probably in the drain past the disposal; see why a drain keeps clogging.
  • A chemical drain cleaner went into the disposal and the sink is still full. Keep your hands out of the water and tell the plumber which product was used.
  • Water drips from the bottom of the unit. Moen notes that a damaged discharge elbow gasket can let water run down between the shell and the disposal and out by the bottom cover plate,[8] so check that gasket and its screws first. If they are sound, the unit may need replacing; see how to replace a garbage disposal.

Keeping it working

Good habits do most of the work: scrape plates first, can the grease, run cold water, and feed scraps slowly. For drains in general, see how to keep drains from clogging, and if the disposal has started to smell, why a garbage disposal smells. Browse garbage disposal repair, find plumbers in Blacksburg, or see every plumbing answer.

If it has stopped working, describe the problem once and licensed local businesses quote it.

Common questions

Can you put coffee grounds down a garbage disposal?
It is best not to make a habit of it. EPA lists coffee grounds among the things not to pour down the drain into a septic system. On city sewer, a small amount with plenty of water is less of a problem, but grounds belong in the trash or compost.
Can a garbage disposal handle bones?
Small ones, yes. InSinkErator's manual lists small bones, fruit pits and ice as things to grind, because the hard particles scour the grind chamber. Large bones, such as beef or ham bones, are a different matter; put those in the trash.
Are eggshells bad for a garbage disposal?
A few are fine, but InSinkErator's manual warns against grinding large amounts of eggshells, along with fibrous scraps like corn husks and artichokes, to avoid a drain blockage.
Should I run hot or cold water with the disposal?
Cold. InSinkErator says to run cold water before, during and for several seconds after grinding, and not to use hot water while grinding. Hot water can carry melted grease into the pipes, where it hardens as it cools.
Is it safe to have a garbage disposal with a septic system?
Virginia Cooperative Extension advises septic owners to keep disposal use to a minimum or not use one at all, because disposal waste speeds up the build-up of solids in the tank. If you do use one, EPA says the tank will need pumping more often.

Sources

  1. [1] Badger Series Installation, Care and Use Manual, InSinkErator. Checked October 26, 2026.
  2. [2] FAQs: Garbage Disposal Support and Advice, InSinkErator. Checked October 26, 2026.
  3. [3] Fats, Oils & Grease, King George County Service Authority, Virginia. Checked October 26, 2026.
  4. [4] Sewers, City of Alexandria, Virginia. Checked October 26, 2026.
  5. [5] Water and Sewer FAQs, City of Salem, Virginia. Checked October 26, 2026.
  6. [6] Septic System Best Management Practices (SPES-380), Virginia Cooperative Extension. Checked October 26, 2026.
  7. [7] Onsite Sewage System Owner Responsibilities, Virginia Department of Health. Checked October 26, 2026.
  8. [8] Leak Underneath: Existing Garbage Disposal, Moen. Checked October 26, 2026.
  9. [9] How to Care for Your Septic System, U.S. Environmental Protection Agency. Checked October 26, 2026.

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