Informational Guide

How To Sharpen Garbage Disposal Blades

Check out our guide on how to sharpen garbage disposal blades to make them like new again.

by Josh Mitchell

Our garbage disposals are the perfect tool for dealing with pesky food waste. With one flick, it all disappears. In a modern kitchen, the garbage disposal works overtime daily, and eventually, the blades are going to get dull.  

When this happens, the waste in our sinks isn’t going to escape as easily. You might consider replacing the entire thing, but is there a way to avoid that? In fact, there is. Follow this guide for tips on how to sharpen garbage disposal blades and keep them working efficiently.  

Short answer: yes! A garbage disposal isn't as simple as two or three rotating blades beneath the drain. There are a few different mechanisms working together at once. The impellers are attached to a rotating disc and move the food waste against the stationary shredder ring, which breaks down the food into minuscule pieces.  

When the shredder ring has become dull, this means it’s in need of a good clean. There are several ways to sharpen and clean your garbage disposal, which will increase its longevity and keep you clearing your food waste for longer.  

InSinkErator Garbage Disposal

How To Sharpen Garbage Disposal Blades (3 Easy & Effective Ways)

There are many myths and facts about garbage disposals which we will discuss later. The best methods for cleaning and sharpening are the simplest; your garbage disposal can be sensitive and should be treated as such.  

Three methods of cleaning and sharpening are listed below:  

1. Ice Cubes & Salt 

Throw a handful of salt into the drain along with 8 – 10 ice cubes, running the cold water at the same time. Run the disposal for up to 1 minute before switching off and leave the water running after for 15 seconds to clear any residue.  

The ice cubes work as an abrasive cleaner when they’re broken down, with the salt scrubbing away any grime leftover in the grooves of the shredding ring. This is what most manufacturers recommend to clean your disposal.  

2. Hot, Soapy Water

A less commonly mentioned method, but just as effective. Fill your sink with hot, soapy water. Once filled, pull the plug, and run the disposal immediately. The water is going to clear away grease and grime, along with freshening up the components.  

Once the water is drained, turn off the disposal and run your cold water for a few minutes to clear away any residue suds in the shredding ring. Once finished, you should notice your disposal grinding the food down easier.  

3. Citrus Fruits 

Cut a lemon into wedges. Turn on your disposal and place them in one at a time with a good stream of cold water. Lemons are a natural cleaner and will also remove any odors that are escaping from your drain.  

Make sure the water is running constantly to allow any seeds and residue from the lemon to clean away. Once finished, fill the sink with water to clear away any leftover lemon.  

citrus fruits

Myths That Do Not Sharpen Your Blades: What To Avoid

You may have heard of some foods or other materials that will clean your disposal. Unfortunately, many of these will do more damage than good, and you should avoid doing them. Even with a good standard disposal, putting these items down there will cause blockages or damage. 


In theory, glass would work well – small shards will clear out the tiny food pieces in the shredder and break down itself in the process. But in reality, no one really knows how big your shards should be, and you could end up jamming the drain or even damaging the shredder ring. Not to mention polluting the water supply! It's just best to avoid putting glass down your sink.  

Should you find glass stuck in the drain, worry not! Follow this guide to clearing glass from a garbage disposal. 

Egg Shells 

It's true that a very small amount of eggshell won't block your disposal, but when eggshell is broken down, it cracks into even smaller pieces and eventually may get stuck in the blades and clog the flywheel. If that’s left for a while, the stench may start spreading from the drain. It’ll be important to clear the eggshells as soon as possible.  


Bones are just too heavy-duty for a standard garbage disposal to break down, and adding a load of bones will eventually clog up and damage your sink. Of course, if a small bone should slip through, that shouldn’t be a problem. But adding a lot will eventually break your disposal, and you'll need to pay out for fixing or a replacement.  

Coffee Grounds 

Coffee grounds should not be put down your garbage disposal. Coffee grounds will indeed remove musty or old food smells, but when coffee grounds are unused, they begin to clump together and form a sticky paste-like substance. This will get stuck in the flywheel or in the shredder blades pretty easily and lead to more problems than solutions.  

coffee grounds in a container

Preventing Dull Impeller Blades (Tips & Tricks)

Your garbage disposal is a handy, heavy-duty tool for your kitchen. But like all of our appliances, there are some things it’s not designed to be used for. If you want to avoid your shredding ring dulling too quickly, don’t put these down the garbage disposal:  


Grease and oil will drain away well in hot water, but once it starts to cool, grease and fats will solidify in the gaps in your blades and flywheel. Oil will also drain slower, sit in the U-bend, and lead to clogging.  


Seeds and fruit pits are just too hard for your disposal to get rid of. Peach pits are especially tough, and your disposal cannot break them down. Their shapes (round, oval, etc.) make them almost impossible to grind down.  

Fibrous Foods 

Vegetables and fruit with high fiber contents will clump together very well – they don't flow down the drain as easily as you think. So avoid putting leeks, apples, pumpkins, carrots, etc., down the garbage disposal.  


Harsh chemicals won’t do any good – they can strip away the non-stick layers or damage metals. You should also never put medications down the sink, as this can affect the water and cause environmental damage. 

People Also Ask (FAQs)

How long do garbage disposal blades last? 

A standard garbage disposal has a warranty of 10 years before the blades will dull. Avoiding any of the items listed above can also extend the lifespan of your garbage disposal.  

Is it better to replace the entire garbage disposal or just the blades?  

It depends on the level of damage. If the system is taking too long to dispose of, or it's clogging up often, there may be a blockage that can be fixed. Other issues such as frequent resetting or no grinding of your foods may mean the whole unit needs replacing.  

Can you tighten loose garbage disposal blades? 

If you can find the loose connection and have the tools to tighten it, then yes, you can tighten garbage disposal blades. Usually, loose nuts or bolts can be fixed easily, but if something happens to the shredding ring, you may have to replace it.

Why is my garbage disposal making weird noises? 

If your garbage disposal is humming, rattling, or gurgling, this will indicate a blockage or damage to your garbage disposal. Check to see if food or debris is stuck in the flywheel. It can also be a sign of a defective disposal; call a plumber if you're unsure.  


A garbage disposal is a valuable tool for any modern home, and it's essential to care for and properly maintain it like any of our other appliances. Keeping fatty or fibrous foods out will keep your disposal going for longer.

If you're ever unsure, it's always best to call a professional and have your disposal checked. Keep the garbage disposal looking sharp and cutting fine! 

Josh enjoys researching, testing and diving into home improvement & DIY products. He has a passion for tools, learning new skills and fixing the everyday problems that arise around the house.