Much of the use of charcoal briquettes depends on the type of briquette. Pure wood briquettes, not the type commonly sold in mass quantity or marketed heavily, are best for use outdoors.
Wait until the briquettes have fully cooled, scrape them out of the grill and scatter them in your garden or on certain plants. The basic pH level in the charcoal ashes will lower the pH of your garden, causing higher productivity in some plants.
However, rose bushes and other high-acidity plants do not need lower acidic levels; do not dump the coals onto them. Also, add used charcoal to compost heaps to lower the acidity of the pile.
Charcoal briquettes made of 100-percent wood have very little binder in them; this binder serves to hold together other briquettes, such as the more popular quick-light briquettes, and the binder is left over after burning. However, in 100-percent wood briquettes, the ashes work well for making various soaps.
Since ash is coarse, it can work as a scrubbing agent. Use it as an abrasive for cleaning metal surfaces or utensils.
Some also suggest using charcoal as a cleaner for white or dry-erase boards. Dipping a cloth in the ash and rubbing it on the board is said to eliminate any marks and provide a clean surface.
Use ash for various tasks outdoors. If you grill often, consider making a path in your back or side yard with leftover charcoal.
Dump the used briquettes on the ground to form a trail, and as people step onto the ash, it will pack down. Or use them in the winter as an abrasive solution for ice and snow.
After cooking, allow the briquettes to cool completely and store in a coffee can or other large, sealed bucket. During the winter, if your car is stuck on snow or ice, sprinkle used charcoal briquettes next to and under the wheels to provide traction.