Kool-aid dies protein (animal) fibers such as wool, silk, and fur (hair). It is popular with knitters for dyeing wool yarn. As it’s food-safe, it doesn’t require special utensils reserved for this purpose as other dyes do. Tamarindo (brown), Switchin’ Secret (light green/tan), and Grape (purple) are popular flavors, because they can be used to tone down the otherwise day-glo colors. A typical formula is one packet of Kool-aid per ounce of fiber, combined with 1/2 cup of water and optionally, a tablespoon of vinegar. Heat is used to set the color, usually by steaming or boiling.