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Can You Reuse Charcoal? Yes, in These 8 Ways so Don’t Throw it Away!

Can you reuse unburned charcoal for your next cook? Is it advised? If so, how? And are there any other uses for only partially used charcoal?

Last Updated: June 23, 2020

A shot of half burnt charcoal in a kamado Joe firebowl

You just paid almost $60 for a bag of premium hardwood charcoal. You dumped half of the bag into your grill, lit it and grilled two juicy steaks for you and your wife. But, it just took a few minutes, and at least half of the charcoal is still unburnt.

What a waste. It may have been cheaper to use dollar bills instead!

Everybody knows what to do with the leftover food, but what about left over charcoal? Have you ever thought about it, or do you just let em’ burn like most of us? Can you reuse it, the partially burnt stuff, maybe even the ashes?

Of course, you can reuse unburned charcoal, and even the ashes have uses you may never have considered. Recycling lump charcoal or briquettes will save you money, reduce waste and help the environment.

So, next time you’re done grilling or barbecuing, don’t just dump those barely or unburnt charcoal pieces, reuse and re-purpose them to get more bang for your buck.

In this article, I will show you how you can properly save the unburnt coal or briquettes for the next time around.

Note: Most of these recycling methods require 100% natural charcoal without additives or chemicals of any kind. Briquettes have additives and are not suitable for all the methods we’ll discuss.

Quality Hardwood Charcoal is Expensive, Don’t Waste It!

Every time you cook something hot and fast, you need to fill up your grill with coals. You usually put in 2 to 3 times as much as you need. Much of the charcoal is either partially charred or unburnt altogether.

Some of us will either just let it burn out all the way, while others will just close the lid and discard them before the next grill. Good quality natural charcoal is not cheap so save every piece you can. It’s easy to do.

Snuff Em’, Sift Em’ and Save Em’

Close the lid and vents to smother the fire the moment you take the food off the grill. As you already know, this will kill the fire from lack of oxygen, and stop it from spreading to the unused part of the charcoal. Let it cool down up to 24 hours just to be sure the coals are out.

Sift the charcoal through a wide mesh screen or use a kick ash basket if you have one. The idea is to knock off all the white ash from the unburnt portion. Every piece of unburned charcoal or briquettes that are still black are combustible.

Save them in an inflammable container or dump them in the bottom of the grill as a base for the next fire.

If You Must Use Water To Kill The Coals

You may have reason to put your fire out immediately using water, especially if you live in a fire-prone area like the southwest.

Use tongs and carefully pick out the coals and plop them into a bucket of water. You don’t want to dump water onto your grill because it will cause rust and it’s a big mess to clean up.

You’ll have to leave the unburnt charcoal in the sun to dry for a couple of days, then store until you’re ready to light your next fire.

Like a Used Car, Used Charcoal Has Limitations

Partially burned charcoal has lost some of its mass and potential energy. Like a used car that already has 150,000 miles on the clock, it won’t go the distance or last as long. You’ll need to supplement the used charcoal with new fuel.

If you’re using a chimney starter, add new charcoal first, or the smaller used pieces may fall through. The reused bits will light up quickly and helps to get your grill going fast.

You can always burn used charcoal or briquettes to save money and time. But, there are seven other things you can do with unspent charcoal. To get the best results, use 100% natural (hardwood, mesquite, coconut, etc.) charcoal.

1. Fertilize Your Garden – Black Gold Agriculture

There is evidence that tribes in the Amazon basin used crushed charcoal to improve poor or depleted soil almost 1,500 years ago. Modern science has backed up the fact the charcoal adds nutrients to the soil, even more so than compost or manure.

You can listen to or read about the evidence in this interview with NPR about “Black Gold Agriculture.”

Many flower enthusiasts, especially orchid growers, believe that adding crushed charcoal to the soil will absorb toxins and increase the alkalinity of the soil. You may have just learned the secret to making the best garden in town.

2. Reduce Odors Around The House

Use a fine-mesh bag and put some of the smaller pieces inside. The charcoal absorbs moisture and odors in the refrigerator and stinky shoes.

Give it a try, but be sure that it does not leak into your shoes.

3. Add Used Charcoal to Your Compost Pile

You can add charcoal to the compost as long as you don’t add the ashes. Too much ash will kill the natural process by making the soil too alkaline.

4. Make Flowers Last Longer

Place one piece of charcoal or briquette in a flower vase under the cut stems to preserve flowers longer. Weigh it down with glass marbles or seashells if it floats, and change the water after 4 to 5 days.

5. Reduce Rust

Charcoal naturally absorbs moisture. Try placing some in a fine-mesh bag or doubled up sock and leave it in your toolbox to help prevent rust.

6. Use It to Shine and Polish

How about brushing your teeth with charcoal? Sounds crazy, but people have use dit as a dentifrice for centuries. In Asia, they love charcoal toothpaste products.

You can use the carbon to polish silverware or take rust off tools. It’s somewhat abrasive so test it out first.

7. Emergency Intestinal Aid

Charcoal carbon is an ancient remedy for upset stomachs and diarrhea. If all you have are some pieces of charcoal and you’re miles from anywhere, chewing a small piece can help absorb toxins and reduce symptoms.

The tablets that you find in drug stores come from “Activated” charcoal. It’s wood charcoal that has undergone an industrial high-temperature process to increase the pores and surface area of the carbon.

A Warning About Charcoal Ash – Do Not Eat IT!

You need to know that unburned charcoal and the ash are two very different things. Ash or potash contains high levels of potassium. When mixed with water it creates potassium hydroxide, the same ingredient as drain cleaner, also called lye.

You must be careful where you throw the ashes because they can change the alkalinity of the soil and are harmful to plants that need acidity like hydrangeas, azaleas, and fruit like blueberries. The alkalinity can ruin new seedlings too.

But the alkalinity can be useful for:

  • Controlling aphids on your tomato plants, and slugs on the ground
  • Reducing Algae in fish ponds by adding one teaspoon per 1,000 gallons.
  • De-skunk your pet by rubbing a handful into its coat to neutralize the stink.

It can also be used for making Lye Soap the old pioneer way:

Save the Planet and Your Budget By Reusing Charcoal

There is no point in letting your charcoal burnout if you don’t need it. You don’t leave your gas or electric stove running while you eat and then turn it off later do you?

Close-up the grill as soon as you’re done the with the cooking. Save your charcoal for another day. Besides, you’ll never know when might run out of toothpaste.

Feel free to pass this article to grillers, gardeners and anyone who has excess charcoal on their hands. If you have any ideas on how to repurpose used charcoal, please let us know in the comments below. And while I have your attention, please go check out my extensive guide to using a charcoal grill for top tips on how to master this form of cooking.

Happy grilling!

Professional member of the NBGA (National Barbecue and Grilling Association)

I'm a self-proclaimed BBQ nut, and the founder and chief editor here at Food Fire Friends.

I love cooking outdoors over live fire and smoke whatever the weather, using various grills, smokers, and wood-fired ovens to produce epic food. My goal with this site is to help as many people as possible enjoy and be good at doing the same.

Leave a Comment


Marjorie Johnson

Have you ever heard of charcoal designed to use multiple times? How does it work?


Mark Jenner

Hi Marjorie,

I haven’t, no, and am sure it cannot exist because once the charcoal is burned, it’s energy is spent and it’s just ash. What I’m referring to in this article, is charcoal that’s been either partially, or even fully burned. Many times when you finish cooking, the charcoal isn’t completely burned through and many people just throw it away. Or if it has burned, there is always a load of ash to deal with.

What this article is aiming to discuss, is what you can do with the partially burned coal, or the ash at the end of a cook, instead of simply throwing it away (which many people do.)



Are there uses for coal that has not been used ?


Mark Jenner (Author)

Yes, I have included them in the article above. If you mean ‘further uses’, then I’m not aware of any above and beyond what I’ve already discussed.