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Heathkit IN-3117 decade resistance box question


I just bought a Heathkit IN-3117 decade resistance box from ebay for $50 dollars, and visually it almost looks brand new.  Everything works and is well within specs, however two of the knobs are really really stiff.  One of them is so stiff it hurts my fingers to turn.

My question is what I can do to alleviate this.  I opened it up and it just has rotary dials on the inside with several resistors connected around the outside of each. I was thinking about squirting just a little WD-40 inside the tight ones but I wanted to ask here first before I did anything.  I don't know if WD-40 will act as an insulator or if it will attract dirt etc.

Also the two connection posts on top have just a hint of oxidation inside them.  I was wondering if there were any household cleaners or liquids that would be good to use on them.

WD-40 has no place in this. WD=water displacer. Use it if your old car's ignition gets wet. Don't use it as a lubricant, because it isn't one, and will gum up after it sits a while.

Possibly a few drops of light machine oil (sewing machine or gun oil) would help. It's hard to know - metal shaft/metal bushing which has corroded? Plastic shaft which has swelled?

Have you removed the knob(s)? On some style switches, it's possible for the knobs to rub if they're located wrong (too low).


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