[Chas]

Blue Showers...

There is risk of phenolic penetration and leakage. Blue showers was intended to polish the contacts as it had grit in the mix for TV tuners.

In a radio, if the circuit is not known, there could be B+ switched, a cleaning product could cause leakage to the shaft and burn out the wafer.

I use 91% alcohol and an acid brush, back up the switch with a clean cotton rag to soak up excess and contaminates.. Massage the brushing all the way around each side of the wafer, then turn the switch in the opposite direction, clean again. Blow dry thoroughly as the alcohol will chill and cause condensation, warming gently the sections will thoroughly dry. Alcohol will remove all the old rosin residue and any other contaminate. Look at the actuation of the contacts each contact should rise/fall as the connection is made/broken, this is a self-wiping action. Black silver oxide still conducts.

De-Oxit applied with a stylus to only the contacts will help, never saturate the phenolic wafer as this will cause leakage.

GL

Chas