I get my lights wet a bit working out in the rain, or on camping. Most the lights I use are SolarForce host. Usually I take them apart and tighten up the switch boot retaining ring. Grease the threads and/or use Teflon tape. Has anyone tried Vaseline for a grease substitute? I’m thinking about using it around the O-rings instead of grease.
Vaseline is petroleum-based. Silicone is used cause it's inert and doesn't dissolve stuff you put it on.
And some extra o-rings are all I use, and I haven’t had any problems, even using my flashlights for bike lights in the rain.
And never look back
one tube should last even the most avid collector a couple years.
Or available at Harbor Freight for $5.99.
-Garry
i have been using super lube for a few months now…it seems like after a while in some lights it becomes black and just makes a mess. does this happen to anybody else? it works great besides making a little bit of a mess…hasn’t stopped me from using it though still great stuff
The black is the alu, you could clean, swab with alcohol and relube if you wished.
I use an electrical contact grease, it seems to work well with no connectivity issues, its used to lube and waterproof electrical connections on vehicles, certainly makes the threads on lights very smooth as someone here commented.
Are you using dielectric grease? I've been using this stuff for years, but never tried it on flashlight threads. A little bit more expensive.
-Garry
When I was a kid my dad always wiped a screw through his hair before driving it into wood. The oils picked up made the screw run in nice and smooth. I guess I picked that up from him, because without thinking I’ll swipe my finger across my forehead, my nose where my glasses always want to slide down and then rub those oils on the o-ring and thread it back down. Never run out of that stuff! So blast me for why I shouldn’t do that……
it is a bodily fluid.
Has anyone tried alternative sources of silicone oils for thread lube?
I have this hair care product (KeraCare Silken Seal) that is cyclopentasiloxane and dimethicone (a.k.a PDMS, one of the ingredients of silicone grease), nothing else.
My friend gets PDMS once a month… you don’t want to be around her when that happens.
Depends how often you wash…
Me, i work in a hospital…
At $17 a bottle it may not be the cheapest way to go about it but it’s got these great features:
• Light looks luminous and shiny.
• UV protection helps prevent damage
Might want to use something that’s made for the purpose though, to be on the safe side. http://www.bhphotovideo.com/c/product/448597-REG/Fantasea_Line_11192_Silicone_O_Ring_Grease.html
This is made for underwater camera housings. At less than $5 it’s a steal. 
My wife also works at the hospital, one of the Top100 in the States, don’t tell me you haven’t noticed how many “nurses” and “CNA”s need to get some personal hygiene 101 classes logged in! Just sayin…
And still it begs the question, we’re talking about an o ring in a flashlight…it gets dirty, blackened with the wear and tear of aluminum on aluminum. It’s a tool. Where does hygiene come into play with a flashlight exactly? Are we supposed to take em in the shower with us and make sure to dry behind their ears? I know, that sounds sarcastic as he, but I’m serious…they’re tools and we use em outside, drop em in the dirt, roll em around on the greasy concrete under the truck, what’s clean got to do with it?
My knives, I clean. They may be used to cut a steak or whatever, so yeah, that’s different! My memory may be bad, but I honestly can’t recall ever licking my flashlight…again, just sayin!
Whenever I can get away with it, meaning the fit & finish of the parts is such that it will work, I prefer to leave the threads & o-rings dry.
I know, I know... but listen. A dry o-ring likely seals a whole lot better than a properly lubricated o-ring that is caked in cat hair. 
Well I already have a bottle but I wondered how it would differ. I’ll try a little on a Maglite. I’m using Argan oil now for my hair…
Do you mean PMDD? If so, I feel for her. 
I tried the KeraCare on my Maglite (first cleaning threads with isopropyl alcohol) and it made it more gritty. Not recommended! >.<
One 500 gram tub of Red Rubber Grease Should last many many many years. Google it , fine for rubber natural and synthetic and a pile of other useful properties.
Of everything I’ve used it on nothing has ‘gone weird’ on me