Burning plants and waste can make a special kind of carbon called biochar that helps trap carbon dioxide. Some minerals in the plants can make the biochar less effective. Scientists found that removing these minerals before burning the plants can make the biochar better at trapping carbon. This means more carbon stays in the biochar, making it more stable and better at storing carbon dioxide. Removing minerals also changes the structure of the biochar, making it more like pure carbon. This study suggests that taking out minerals before burning plants can make biochar a stronger tool for fighting climate change.