You can create a sort of mini vacuum by warming the wood and placing it into
the dye. Lower pressure of the heated and expanded air will draw as it
cools.

Reminds me of a industrial potato peeler at a french fry factory I
once visited for work. They load up a 1000lbs of potatoes in a
pressure vessel. Pressure it up to maybe 100 psi or so (can't remember
the exact amount), hold it for 5-10 minutes, then release the pressure
all at once. Blows the skin right off the potato.

Mitch