Valve cleaning method

A valve cleaning method comprising the sequential steps of:

• (1) providing a plurality of valves each having an inner surface to be cleaned;
• (2) cleaning the inner surfaces of the valves a first time with deionized water to remove particles from the inner surfaces of the valves;
• (3) cleaning the inner surfaces of the valves with a first chemical mixture to remove organic matter and remaining particles from the inner surfaces of the valves, wherein the first chemical mixture comprises isopropyl alcohol, acetone, and deionized water;
• (4) cleaning the inner surfaces of the valves a second time with deionized water;
• (5) cleaning the inner surfaces of the valves with a second chemical mixture to remove metal impurities from the inner surfaces of the valves, wherein the second chemical mixture comprises nitric acid and hydrogen peroxide;
• and
• (6) analyzing a sample of the second chemical mixture used for cleaning the inner surfaces of the valves to determine an amount of the metal impurities removed from the inner surfaces of the valves.