TRI FLY OCTANE 100% Synthetic Synthetic sole SHOE CARE AND MAINTENANCE: Clean mud off with a damp sponge and then stuff the inside of the shoes with paper to help absorb moisture and maintain shape. Never clean shoes in a washing machine. Keep the outsole clean by scrubbing with a soft brush when needed. Air dry at room temperature. Do not dry the shoes by a fire, radiator or other heat source. Do not leave them in your car on a hot day. Extreme, direct heat can cause the materials to dry out or crack. This will damage your shoes