Hello Jeff,
/ubbthreads/images/graemlins/evilgrin07.gif I think it depends on what you eat... and drink... /ubbthreads/images/graemlins/nana.gif
My hand sweat does not seem to effect the lights that I use regularly, with the exception of my brass Peak lights.
I just checked my Mag bodies, ARC LS, ARC AAA, Peak AA, LionHeart, Aleph, TigerLight, L4, E1e, and Blaster Jr, and do not see any problems at all.
Of course... your mileage may vary...
Tom