There is still plenty of time this summer and fall to grill your favorite foods. But when you are finished barbequing those delicious steaks, portabella mushrooms and peaches (skip the blue cheese and serve them over vanilla ice cream), what are you supposed to do with your leftover charcoal? There are ways to recycle and reuse both burned and unburned charcoal. Not the in the traditional, “chuck it in the recycling bin” kind of way. But definitely in a “keep it out of the trash” kind of way. The key to recycling charcoal is to use products that do not have additives. That is something you might want to do for a variety of reasons.

What is charcoal made of?

Charcoal is made of wood that has been burned at a very high temperature for a very long time. The process burns off all the water, tar and other things typically found in wood. What is left behind is mostly carbon. When those blocks of carbon are relit, they create a heat source that burns hot and even. That is what makes them so great for cooking. Many charcoal briquettes contain additives like coal, borax, sodium nitrate, petroleum and lighter fluid. It is also possible to buy organic charcoal that contains only wood and what one website calls “a vegetable-based starch binder.” Modern charcoal falls into two camps: briquettes and lump charcoal. Serious Eats says briquettes “are kind of like the fast food of charcoal; they’re cheap, reliable, can be found on almost every corner, but you really don’t want to know what’s in them.” However, they are quick to point out that they will burn more reliably for a longer period of time than lump charcoal. There seems to be no consensus on which is better. The website AmazingRibs.com has a fantastic article that gives plenty of details on how charcoal is made, how it works and how you can make it yourself. Charcoal manufacturer Kingsford shovels more than 200,000 tons of wood into their charcoal-making furnaces every year. When you think about how many other charcoal manufacturers exist, you realize a huge amount of charcoal is produced every year.

How to recycle used additive-free charcoal

Charcoal is not something you can just dump in your recycling bin and be done with. If you want to recycle it, you will need to get creative. Before you do anything with hot pieces of charcoal, make sure you have completely extinguished the fire. If the charcoal is in a contained area like a grill, let them sit for up to 48 hours. If they are in a fire pit or another place where sparks could escape, carefully pour water on them. Stir the pile well, then pour water on them again. Once the steam has died down, watch for smoke or hold your hand over them occasionally to feel for hot spots. You can also use long-handled tongs to pick up individual pieces and dunk them in a bucket of water. Once the charcoal is completely cool, you can work on recycling or reusing it. This blog post details a technique for reusing charcoal when you grill. The author swears the briquettes will be ready to use faster and your food will taste better. Plus, you will not need to spend as much money on charcoal. Charcoal manufacturer Char-Broil has several great suggestions for putting used charcoal to work. Spent charcoal with no additives can be used to fertilize plants. The potash (potassium) in charcoal can raise the pH of your soil, so do not use it on acid-loving plants like berries and azaleas. It can also harm young seedlings, so you should only place it on established plants in your garden. Char-Broil also suggests mixing charcoal and lime and spraying it around areas where you want to deter pests. The ashes themselves can be used to reduce algae in fish ponds, shine silver and make soap.

How to reuse unused additive-free charcoal

An article on This Old House describes 10 ways to put unused (additive-free) charcoal to work around the house. Their suggestions include adding it to compost, using it as an air deodorizer, adding it to cut flowers to make them last longer, and using it in place of sidewalk chalk to draw hopscotch squares. Fuel company Peninsula suggests using the deodorizing power of charcoal to draw the smell out of old shoes. It also recommends using its moisture-absorbing properties to keep metal objects like tool chests from rusting or deicing salts from clumping.

Can you recycle charcoal with additives?

Because charcoal with additives contains potentially-dangerous chemicals, it cannot be recycled. Most solid waste districts advise you to wrap completely extinguished briquettes in aluminum foil before placing them in your trash can.

Alternatives to charcoal

One way to avoid throwing away charcoal is to stop using it altogether. Gas grills are a good alternative to charcoal ones (although then you are burning fossil fuels, which is a whole other issue). If you want to control exactly what goes into your charcoal, you can make it yourself at home. This is also a great way to recycle things you may have sitting around the house already. A website called Buzzle gives instructions for making wood briquettes in an old metal barrel. DIY Network also has really detailed information about creating charcoal, including some specifically recommendations on which woods to use. It is also possible to make charcoal from other substances such as paper. This YouTube video gives instructions for turning recycling paper into something you can put in your barbeque, fire pit or smoker.