I'm sorry, I'm sure this probably has been discussed. But just for my sake (and perhaps a few others), what if anything do I need to do to maintain my ARC LS (terrific light) in good working order?
Every few weeks I clean the threads of the battery compartments with my finger nail and a Kleenex. I place my thumb on the inside of a compartment and spiral my way up and down the threads with the Kleenex on my index finger.
For the LS head it's a little more challenging to clean the threads. I wad up some Kleenex between the threads and my index finger and just rotate the head with my other hand.
I also put just a touch of Vaseline on the threads to keep things lubed.