I use faucet grease. Very inexpensive and every hardware store has it in stock. Only a couple of bucks for a lifetime supply size.
Mmmmmmm, Fawcett grease.....
sweet.
i also like Fairchild and Fonda :love:
Fonda :-(
That Fawcett will never be greased again 
Sadly, no... 
But as kreisler noted, there's always Fairchild Paste and Fonda Wax!
After asking about this lube and having not much of a response, I picked up some of the Contralube 770 lube today.
http://www.maplin.co.uk/contralube-770-connector-lubricant-346030
It's excellent clear synthetic grease with good consistency. I've applied it to the threads of one of my Solarforce L2P hosts with excellent results.
Highly recommended for us UK people!
i had asked the superlube company about the grey buildup in the suberlubed non-anodized bare aluminum threads (e.g. in Quarks or Klarus P1A) suspecting that the superlube oil would dissolve the unprotected aluminum and the answer i got was:
and yesterday the maker of Nano-Oil (a substance which i assume works a little better on unanodized aluminum threads) who is wary of making any kind of promises regarding the performance on unanodized aluminum threads commented:
Re: Comprehensive Grease and Lube Thread
Originally Posted by Nano-Oil.com
I do agree that my response was cryptic to a level, I do apoligize but there are reasons,
I cannot & will not promote Nano-Oil in CPF
ex: I always use the verbage "use a good anti friction lubricant of your choice"
From google cache one can see that 1 or 2 years ago he was selling Nano-Oil on cpfmp but then he stopped the dealer's subscription on cpfmp. In any case, as far as i can tell the original problem of
unanodized soft bare aluminum threads (male rubbing against female)
is still unsolved. But it's good to know that superlube does not dissolve the material. As stated earlier, superlube does kill the friction in the bare aluminum threads. Feels really good and smooth. (Not so good on Titanium threads, though). No wonder that nobody wants to promise anything or promote the oil further on CPF: we flashaholics are highly criticial (some with asperger's) and much of our Chin*se threads are just made of cheap aluminum quality. I'll continue to assert and promise that there is no lube on earth (< 20$) which solves the original problem to kreisler's satisfaction.
With typical lube (superlube, nanooil, silicone oil, etc.) we will always end up with grey crap in our unanodized aluminum threads. Simple as that. It's maybe comparable to the example of stainless steel kitchen countertops: when you try to clean/scrub the kitchen counter with a dishcloth, the dishcloth will end up grey from the stainless steel abrasion.
I really wouldn't worry about the grey gunk! You seem a little too concerned about it!
It will not effect the threads in anyway and the lube will still do it's job even if it's a different colour. The only slight annoyance is when you place the light down during cell change over, the discoloured lube will leave a mark (if your not careful) on surfaces.
Apart from that, just EMBRACE the grey gunk. 
You don't like the color of your thread-gunk? Order now: "gunk coloration kit" from Dino Direct.
I use silicone RC car shock oil and or grease. I had a bunch of different thicknesses from years ago. Everything from really thin oil like to grease. I put on what I think I will like, if I dont, I wipe it off and put on a different one. You dont need PFTE or anything like that since there is no friction. Thickness is key. Each light responds different to the thickness. Any petroleum product will mess with the o rings.
There is friction when you are unscrewing or screwing the tail cap. as for he o-rings, I wouldn't worry too much about them. They are easily replaced and they are cheap.
I don't want to hijack the thread. Just a question.
I found I already have this Syon Lubit-8 at home. It contains Teflon.
Will it be gentle with o-rings?
Sould be ok, but this does contain Petroleum products, so no good for pure rubber o-rings.
I emailed the CEO of SuperDuper Lube. I asked why I felt a slick substance on my fingers after applying the grease to my threads. I thought it might be from the thermal break down of the molecular bonding agents or maybe the Teflon atoms were outgassing a strange form of hyper lubricity coagulating gel.
Here is his response: “it is because you got grease on your fingers, you freaking NERD! If you ever waste my time with your geeky emails again, I am going to come over to your house and crush your skull with a rusty tire iron. Get a LIFE!”.
Seemed kind of harsh but I see his point.
Sorry to dig this thread up but I am having a job finding some suitable grease for my L2P in the UK, it arrived completely dry. The battery end of the tube is bare aluminium and the other is anodized. Could I get away with some of this for the anodized parts/o-rings:
http://www.ebay.co.uk/itm/120822334806?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
And some vaseline for the bare alu? Or if anyone can point me to a teflon-based one that suits everything, is cheap and available in the UK that would be great!
As far as grease goes, I have been very happy with plumbers faucet grease, very cheap from the hardware store.
Maplin silicone grease.
Or what I use:
Engine oil dispensed from a syringe. SAE90 if you want to have sticky stuff - I'm using SAE 10-40 engine oil. Wipe off most of it and there will be enough left to do the lube thing. If you can't get a syringe or two, PM me. I work in a hospital.
If the threads are anodised and sloppy I use PTFE plumbers' tape. Works very, very well.And costs half of nothing!