Ill admit im learning fast and doing things most never would with modding electronics and internals, But i still learn new things each day.
This was a big one tho, And it was detrimental to the output of every light i owned.
Silicone grease ONLY goes on o-rings and O-rings only, I would put it on every thread of every flashlight i owned.
Once i found this was causing my lights to loose current draw i started testing each light before and after cleaning. The biggest improvement was my BeamTech XML 2x 18650 that was pushing .9A prior to cleaning and afterwards when to 1.6A's
I also have a suspected area that also that can cause further issues and that thermal compound on pills threads and wrapping hosts with a combination of foil and compound as the negative electron flow rely's on there areas some more than others to get current to the driver.
Ive cleaned all my lights and removed all area's i feel that are suspect. I will be going back and re-wrapping the P60 drop-ins but with bare aluminum foil only. That should actually increase current than deter it if its bare and still help wick heat away.
I use the thin lube that came with a Panasonic beard trimmer.
Some people said the they like the thick oil which never worked all that well for me. It's hard to remove and doesn't seem any better than the thin stuff. The nextorch type "cream" is coming in the mail (3+month shipping from DX), and I don't expect it to be much better.
So, moral of the story is to use thin of a lube as possible.
I have been using Super Lube for many years, it is very thick like Vaseline and is dielectric. I originally started using it for tuning up cars when they still had wires and distributors now I use it on my flashlights. The big container I have is at least ten years old and will probably last a lifetime. Anything with threads that I want to be able to take a part again gets some and o rings love it. I have not noticed any reduction in current in before and after tests but I use bare aluminum foil on drop ins only. I have noticed the cutting oil that comes on some lights is very bad for current transmission and cleaning it off and replacing it with Super Lube has been very effective for me.