Cotton. Wool. Nylon. + more. Celebrating 100 a century. Rit Will Dye: Cotton. Linen. Rayon. Silk. Wool. Nylon. Package color reflects approximate results when dyeing white or off-white 100% cotton. Non-toxic + safe for sewage & septic systems. Conforms to ASTM D-4236. ritdye.com. Before dyeing visit ritdye.com for detailed instructions and a library of over 500 color recipes. Made in the U.S.A. of U.S. & imported materials.