We would highly recommend using the Hegen Bottle Brush and Teat Cleaner with undiluted baby bottle detergent to clean the pump module, grey silicone seal and manual diaphragm. As the valves are delicate, we would highly encourage you to gently massage them with your fingers using undiluted baby bottle detergent to break down any milk residue.
We would discourage the use of cleaning with a wired bottle brush as this may cause scratches to form. Chemically aggressive or abrasive cleaning agents, solvents or anti-bacterial cleaners are also not recommended as this will damage the product.