Can You Reuse Charcoal Briquettes? No! But Yes, in These 7 Ways, so Store It
Reduce, reuse, and recycle. These are the mantras of the environmentalist movement, though they're popular with the frugal, too. You can reuse many items, though it may take research to learn how. Can you reuse charcoal? The answer is: it depends on the application. Here are a few ways you can reuse charcoal pieces and charcoal ash.
7 Ways to Reuse Unburned Charcoal
1. Reuse Charcoal Briquettes to Cook
Can you reuse charcoal briquettes? The answer is no. They remaining briquettes will never get hot enough again, because the fillers that made them burn so hot literally burned away. Do not try to reuse them by adding lighter fluid.
You'd be better off burning leftover pieces of hardwood lumber. The hardwood lumber is the same slow-burning material that's used in many charcoal briquettes. You can throw in pieces of mesquite wood or flavorful wood chips when you're roasting something on the grill for a long time.
If you're going to cook something quickly and you have some large leftover briquette pieces, you could cut off the burned portion and try to reuse them. Just add a few fresh lumps to the briquettes to get enough heat. In this case, you may need a little lighter fluid, because it is hard to light. But too much lighter fluid will cause a flash burn without generating the long-term heat you need to cook things properly.
How you can reuse charcoal for smoking, and how to store unburned charcoal for the next grilling:
A common mistake is trying to reuse leftover charcoal or wood by simply throwing the material in the grill or smoker and then lighting it. Knock ash off the briquettes. Remove ash from the grill. Maximize airflow, or you're guaranteed to have under-cooked food. You can put the old charcoal in the chimney to get it hotter, faster, but you must supplement it with fresh charcoal. You'll need at least half fresh charcoal to successfully reuse the partially spent pieces, stacking fresh pieces on top of the used ones. In this way, you can reuse charcoal for smoking and grilling. Furthermore, you can't really reuse charcoal that is completely spent.
If you want to reuse the charcoal, cut off the airflow as soon as you're done grilling instead of letting it slowly die down. If you're burning them in an open fire, you could try to sweep them into a heat-proof and fire-proof container. A covered metal garbage can is a good option.
We don't recommend dousing coals with water to prevent them from turning into ash in the hope of reusing them. Dousing the fire with water instead of letting it burn down can generate a lot of smoke or even dangerous steam. A safer choice is picking up the smoldering charcoal pieces with tongs and dropping them in a container full of water.
Mass-produced charcoal briquettes are cheap enough that you shouldn't be trying to reuse them all the time. On the other hand, hardwood briquettes like those made from cedar or apple wood are expensive enough to be worth trying to save and reuse.
2. Use Charcoal as Fertilizer
Crushed charcoal can be used to improve your soil. This is why charcoal may be mixed into compost or manure or used as a soil amendment in its own right.
This requires crushing the charcoal and then mixing it into the soil. It will increase the alkalinity of the soil, so make sure this change in pH is what your plants want or need before you do this. For example, adding crushed charcoal is great for many flowers but not so good for vegetables unless you have acidic soil. Do not add charcoal or charcoal ash to the soil around blueberries, azaleas or hydrangeas. They need acidic soil.
On the flip side, you can put a piece of clean used charcoal in a flower vase with cut stems. This will extend the life of the flowers. You'll need to change the water after four or five days, but few cut flowers last that long anyway.
Another option is adding charcoal to the compost. However, you just want to add the crushed charcoal, not ashes. If you add a lot of ash to the compost pile, you'll halt the natural processes that make compost such valuable fertilizer.
3. Turn Charcoal into Deodorizer
Can you reuse charcoal to create a home-made deodorizer? The answer is yes. Put smaller pieces of dry charcoal in a fine mesh bag. We're assuming you've removed the ash and dirt from it. Then you can put it in the fridge or your gym bag to absorb both moisture and odors. Just don't let the charcoal dust get into your clothing or onto your food.
Note that you can use pieces of charcoal the same way in your toolbox. Put the spent charcoal in a mesh bag or even a sock. Then put it in a toolbox or metal cabinet to prevent rust.
If your pet has been hit by a skunk, you can rub charcoal into their coat to help neutralize the smell. It will need to be rinsed out of their fur like dry shampoo.
4. Use Charcoal to Clean
Charcoal can be used in toothpaste, but we're not going to recommend reusing charcoal to make your own dental cleaning produces. However, you can use it to clean items around your home. For example, clean pieces of charcoal (including used ones with the burnt pieces cut off) to rub the rust off tools. Note that charcoal is abrasive, so test it before you use it all over the tool. If the charcoal isn't too abrasive, you could even use it to polish silverware. Note that unused pieces of charcoal are the most effective for this purpose.
5. Use Charcoal as a Stomach Reliever
Charcoal can be used to treat digestive upset. In theory, eating a small piece can reduce symptoms and absorb toxins. However, we'd recommend using activated charcoal tablets from the drug store instead of making your own. It has been made specifically for human consumption. Never eat charcoal ash. The high levels of potassium in the ash are not healthy. In fact, if you mix charcoal ash with water, you get potassium hydroxide. That's the main ingredient in lye, a substance often used as a drain cleaner.
6. Make Soap from It
Soap can be made with or without lye, and there are hot and cold soap-making processes. We already mentioned that charcoal ash mixed with water makes lye. Soap containing lye is an excellent way to clean heavy stains from clothes, and it can be used to clean dishes and floors, too. On the flip side, soap with a low level of lye and a high level of fats is the default choice for moisturizing your skin.
How do you make soap with lye?
Most recipes called for two pounds of fat like tallow, lard, or palm oil. The hot soap making process involves adding lye to hot water, dissolving the lye completely. Don't add water to lye, because splashing lye can burn your skin. We recommend wearing rubber gloves and safety goggles during this process. And have good ventilation while you're working, because the fumes can irritate your lungs.
Melt the fats down to a liquid. (This is called rendering.) Then add the fatty liquid to the lye mixture. Stir quite a bit to create a blended mixture.
Once you have a pudding-like consistency, let it "cook" for an hour. Use this time to prep your mold. The line that with parchment paper so the solidified soap is easy to remove from the mold. Once the liquid has cooked, put it into the molds. It will need to cool and harden for at least 24 hours. When you remove the soap from the mold, you can cut it into smaller pieces. Give it extra time to dry to make it more effective, though it can be used at this point.
Know that you cannot reuse any tools that touch lye to cook later on. You'll have to neutralize the lye with white vinegar, water and soap, and even then, we don't recommend cooking with it. Some people ensure that there is no liquid lye leftover in the soap by adding a little more fat than the recipe calls for. That's called "super fatting".
This soap doesn't generate suds, but that makes it suitable for high-efficiency washing machines as well as cleaning nearly anything else. Or you can rub it directly onto stained clothing and tools to remove grease and oily stains.
7. Use Charcoal for Pest Control
You can sprinkle crushed charcoal on the ground. This will help kill aphids and slugs. You could mix ash, lime, and water to create a mix that will deter beetles. Spray it around the perimeter of the garden, not on the plants themselves.
You can spread wood charcoal ash around an outdoor bird cage to help deter lice and mites. This is a cheap, effective solution if you have a chicken coop.
Do you have too much algae in your fish pond? Add a teaspoon of ground-up charcoal to the fish pond, if it contains at least a thousand gallons of water. We do not recommend using leftover charcoal from your grill in your aquarium water filter.
If you made lye soap, you can use it to treat bug bites, poison ivy, and poison sumac. However, it is too drying to be used to clean the skin on a daily basis.
There are a number of ways you can re-use charcoal. However, this often requires prior planning or having a hobby where the charcoal and its byproducts can be reused.