I've used my Leatherman Wave extensively for expedient food prep.  After I am done, I wash it off and open it up to air dry.  I hit the joints with a little mineral oil and wipe off the excess.  I might occasionally wipe it down with my tuff cloth afterwards.  
As with my cast iron, the only time I ever had my Leatherman rust up on me was when she put it through the dishwasher.  
Izzy, I came to learn that anything with steel in it will rust eventually in Florida.(LOL)
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)