Okey, dokey, please remember one more time that YMMV.
For my lights (and use what you want on your own at your own pleasure and/or risk) I use a pure silicone grease I got at a dive shop or a pure silicone grease from an auto supply parts store. That is all I will use.
BTW, the stuff from the auto parts place came in a very small tube that's sold in a cardboard/blister pack. Interestingly enough it is sold in two sections of most auto parts stores and is the same product. If forget which was priced higher but there was about a $2 difference between the brake grease and electrical connection lube. Same product in the same tube in a slightly different package -- buyer beware!
There are electrical parts lubes that will conduct, so be careful how you use those.
Of course there are other products but what's described in post #18 is what I use and have used for years.
There are still o-rings out there that do not like any petroleum products. Use anything other than pure silicone lubes at your own risk. I've had only one o-ring problem and that was with a RR (River Rock) 2xAA light and was a quality issue not related to lube. I never replaced the o-ring in that light and have had no problems but it's a light that stays in the bathroom for emergency use and it's OK for that. Any other light I have ever owned has been treated carefully.
I am way too poor and way too cautious to treat my few lights with anything other than extreme care. I use the ones I have a lot and depend on them and the ones in the car very well could literally mean life or death. You might treat your lights differently, but I take mine seriously.
Do some searches (hint, hint!) and you find a lot of information on this topic -- it pops about about every 12.3 days in some form or another and that wears thin for some people so I kind of expect to read some snide comments when I see a new thread on this old topic.
There will always be new products coming out and different uses for things that have been around for years. I've done a lot of research and have had great success with the way I take care of my lights. Somebody can use peanut butter for all I care, but being cheap or being too innovative can render a light useless at a very bad time.
One last time then...
- I use pure silicone lube. There are different viscosities, so read the manufacturers info and MSDS sheets, do a search on the lube, and use whatever lube you get after getting some information.
- I clean the threads and the o-rings if needed on a regular basis but I don't take things apart unless I think it's needed. Too much preventive maintenance can cause undue wear and tear.
- I use clean shop rags that have only been used for this purpose, for cleaning and if the part to be cleaned is small or hard to reach I will use cotton swabs. Be very careful of lint since it can cause scratches, can jam threads, and can cause more crud to collect. Really nasty crud gets gently removed with a clean toothpick.
- Never use paper towels, toilet paper, or facial tissue to clean lenses, optics, or threads. Paper is more abrasive than you think.
- Don't over lube. I apply grease a small dab at a time and I use clean fingers. I was my hands very well before I start and keep another clean shop rag to wipe them. You can always add more lube if needed. I wipe off any excess before I put the light back together.
- Here's what I probably consider the most important part. Less is more. Don't over lube or over clean. Don't rip the lights apart for cleaning every other day. Don't overwork the preventive maintenance thing. Too much of a good thing is usually a bad thing. Don't be too aggressive with cleaning and taking things apart. Start out on the easy end of things and work up from there. Don't do anything that cannot be undone. Certainly no maintenance is bad and any lube will eventually dry out. Clean as needed and lube on a regular basis. I find that once or twice a year is enough under most conditions.
I live in upstate NY and the weather ranges from as low as -15 F to as much as +98 F. We get snow, rain, mud, and dust. Not the most extreme conditions on the planet but a good example of a little bit of everything. I've never needed a light and have it ADASTW. I figure that what I've been doing works OK, but again, YMMV.
