There are several ways. One is to use a microwave. Another is to use a dehydrator. Both will work faster if you freeze the green blanks first, as the freezing breaks down cell wals when the water in the cells expands, allowing the blank to dry faster.
I have never used a microwave, but here are the instructions someone gave me.
weigh one blank and put it in the microwave for 2 minutes at normal cooking settings, let it cool down and re-weigh it, if they is a weight difference, the blank is not dry and will require a few more bursts in the microwave but this time, you go for 30 seconds at a time with cooling in between. Weigh it after a couple of 30 second bursts, if it continues to lose weight, continue doing those 30 seconds bursts until the wood/blank stops losing weight, the wood/blank is then dry...!
Sharon