Yes, basic cleaning is recommended before first use of a new Grayl UltraPress bottle. Disassemble the unit by removing the Inner Press and Outer Refill. Hand-wash all parts except the purifier cartridge with warm, soapy water—this includes the cap and outer bottle. Do not wash, soak, or rinse the purifier cartridge, as it contains sensitive filtration media that can be damaged by water exposure before use. After washing, rinse thoroughly and let the parts air dry. Before using for drinking water, you may press clean water through the assembled unit once to ensure it's fully primed.