As the vinegar boiled, Hermione removed the Knuts and flaked off the greenish rust that had begun to form on them. Verdigris was a crude antagonist for silver in spellwork, and would soon lose its potency—but it was better than nothing. She mixed a paste of verdigris and honey, turning it into poultices for the worst of the wounds, and whispered spells over them as she worked. The woman with the burned face let out a sigh as the poultice was applied. The four wounded men unstiffened slightly.