HP 67 cleaning: which silicone grease for the switches?

[Helix]

(06-22-2019 03:44 PM)Dave Frederickson Wrote:  A dielectric grease is preferred, like Lubriplate DS-ES.

Thank you. So, it's a lithium grease.
As I was eager to see the result of my cleaning, I used plumbing silicone grease. I can confirm that the calculator now works perfectly!
Even one mushy key has recovered its firmness, probably because a particle of dirt was encrusted on one side of the key, preventing it to press the center of the "dome".
I am more than happy!