The idea of dropping a Duo-Art piano or whacking its stack to reseat the
valves (cross or round) after moving is just about the craziest thing
I've ever heard, because the best method is also the quickest and
gentlest -- as well as apparently being TOO simple for most people to
think of.

Before you even plug in the piano, just blow air into the tracker bar.
Use your lungs, a dust bellows or vacuum cleaner.  But NEVER an air
compressor, as that could damage the pouches.  Blow into all the holes
several times, not just those connected to the stack.  That will seat
the valves well enough to get the instrument playing nearly as well as
it did before moving.  Then, for good measure, run the test roll through
the repetition test several times.

Most cross-valve stacks have 88 notes; so don't neglect the four notes
at each end, which may no longer be connected to the tracker bar or
included on the test roll.  If these eight valves aren't properly,
seated the stack will leak like a sieve, and no amount of playing will
correct the problem.  Hopefully you can pull off plugged tubes or
squeezed nipples and make these eight notes repeat a number of times at
full volume before restoring them to non-playable condition.

Jeff Wood