Dear B.B.,

Hope you're well and stay so. The valves need to be cleaned, but NOT lubricated. Lubricants will hold micro-particles of dust in the air, that passes through the valve. That dust is will cause a valve to cease to work smoothly.

Cleaning is best done with cotton-tipped swabs, moistened with solvent. Some may use alcohol. I prefer to use methyl ethyl ketone (MEK), which strips away dirt and leaves metal surfaces as close to surgically-clean as one can get. MEK is very flammable, so should be used with plenty of ventilation. Do not smoke or have in the work area any other source of ignition. MEK is also carcinogenic, so wear gloves.

To keep solvent from getting into the valve's electrical "compartment", keep the electrical connector pointed upwards at all times. Use swabs until there's no more dirt in the valve's "mechanical area". Then, let the valve sit for a few minutes - with the electrical connector pointed upwards - to allow any solvent to evaporate.

If cleaning does not restore smooth operation, then it is time to replace the valve.

Hope this helps.

Yours faithfully,

Spook