Using Nipple Brush to Clean Bottles: Wet sponge before use. Fill bottle half way with hot soapy water. Push sponge end inside the bottle. Push sponge end inside the bottle. Use sponge end to clean all areas by twisting and moving back & forth. When the bottle is clean, rinse it thoroughly and then it can be sterilized. Rinse and allow sponge to dry naturally. Using Bottle Brush to Clean Nipples: wash nipple in hot soapy water. Use the specially shaped brush to clean inside of nipple by pushing it completely inside of nipple. Twist the brush while holding outside of nipple. When nipple is clean, rinse it thoroughly and then it can be sterilized.