Needs a few days for all of the wood to reach an equilibrium. If you google up the topic, you'll find some great write ups on it.
Basically, I just wait for a day when my wife is out, put the blank in a zip-lock, microwave it on 50% until the bag starts to inflate from the steam, pull the blank out and wrap it in paper towels, let it sit for 30 min or so, and then repeat until it's dry. Make sure the bags and towels are dry.
It works pretty good. If you leave it in the microwave for even seconds too long you'll toast the blank though so babysit the thing.
