I don't know the answer for certain, but I would think that nothing will reverse the cracking or splitting that already occurred. Soaking the blanks in water will cause the fibers to expand which will more than likely cause more splitting.
Your best bet might be to cast the blanks in resin under pressure. Alternatively, you might just turn them down and fill in the cracks and voids with crushed stone or a mixture of sawdust/ca. Filling the cracks with thin CA before turning will also help.