I take them out of the box, clean the cavities with a Q-tip and alcohol, debur the pins, loosen the pin guide rods half a turn so they slide freely, put a very light, caramel haze of butane smoke in the cavities and tips of pins, mount the handles, lube the bottom of the sprue plate and pivot bolt,dunk the front bottom edge in the melt until lead won't stick anymore and the pivot pin starts to smoke, and start casting.
Preheating a few time oxidizes the cavities slightly and prevents "tinning" of a fresh mould. A little soot accomplishes the same thing only faster and by the time it wears off, the patina has started.