Nowhere in my previous post did I suggest using a conductive grease. Also, I did not intend to imply that this is necessary or even desirable. It is not. Conductive materials can have a nasty habit of migrating to an area where this conductivity is not desired. For example, there have been a few posts by members who have tried graphite based lubricants with undesirable results and a nasty mess as a bonus.
I did say that what you do not want is any material that will interfere with the conductivity of mated parts.
The majority of all flashlight manufacturers that specify a lubricant, recommend silicone grease. (I believe Mag still recommends petroleum jelly.)
Why? Because silicone grease accomplishes the four major functions that any lubricant would need to provide.
1. Lubricate and condition o-rings to limit cross-sectional distortion, eccentricity and surface abrasion.
2. Lubricate the threaded parts to limit galling and oxidation.
3. Provide a physical barrier against the intrusion of water, dust and other contaminants.
4. Accomplish 1-3 without compromising mechanical or electrical operation.
I appreciate that CPF members in general are a curious and experimental group. It is one of the main reasons that many of us are here. The are many hundreds of lubricating products available for us to try. Some will do serious damage to plastic and rubber parts. Some will perform the necessary functions marginally. Some, no doubt, will function perfectly. Which are which? Who knows. Experimentation and anecdotal reporting of results is all that we will have to go on.
Maybe, sometimes it is better to not reinvent the wheel. NyoGel may seem rather expensive. I am three years into my 50 gram jar, and have at least as long to go. I feel that I am getting the function and protection that is required, and that my flashlights are being properly maintained and preserved.
As always there are other avenues and opinions. That is just the road I have chosen.
Mark