To wash capsule filters with a Poly Ether Sulfone (PES) membrane and a pore size of 0.2 μm or 0.45 μm, it is generally recommended to use a mild detergent solution. Sodium hydroxide (NaOH) should not be used for washing these filters due to its potential to damage the membrane and affect its performance. Avoid using NaOH or other strong chemicals, as they can degrade the PES membrane and compromise its integrity and performance.

Instead, follow these steps to clean the filters:

1. Mild Detergent Solution: Use a mild detergent solution, such as a 0.1% to 0.5% solution of a non-ionic detergent.

2. Rinse with Water: Thoroughly rinse the filters with deionized or distilled water to remove any remaining detergent.