Cleaning Hot-Cathode Ion Gauges

Soak the gauge in a 10-20% sodium carbonate solution. Gently heating the solution to 30°C will accelerate the cleaning process, which should take about 15 minutes. 

Rinse with copious amounts of water, then let the gauge soak for about a half-hour filled with distilled water. Repeat the distilled water soak two more times. 

If the deposit is brown, the offending contamination is probably cracked hydrocarbon vapor. This deposit can be cleaned as follows  

Soak the gauge in a 10% solution of potassium hydroxide and let it stand for about a half-hour. This soaking may have to be repeated with a fresh potassium hydroxide solution. 

If there is a discoloration of the electrodes, gently shake some hydrogen peroxide in the gauge until the discoloration disappears. 

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