With apologies to Leif and his disciples, not to mention all & sundry agnostics and disbelievers. This should alienate all sides of rcw in one post, but I won't go quietly into those dark splits and cracks.
I have some NIP logs over two years old with pith left in that have not cracked, split nor decayed. They are a little dry, but turned as end grain, they cut nicely and finish well. Anecdotal, of course, and perhaps works only in S.E. Fla. and only for me, but if you try it, you _might_ like it. This is what I do with NIP without blushing. I'm not a chemist, arborist. botanist, dishwasher, nor manicurist, but I do turn NIP.
I let fresh NIP (and only NIP) logs lie in "sunshine and in shadow" on the ground for one or two moons. Then I debark, pressure clean and rough turn, leaving tenons and/or center dimples. Then I slop any brand of dish detergent liberally over the entire blank. Then I store the blanks covered and off the ground until I want to turn them in the years to come.
Adverse comments, questions of senility and implications of stupidity are expected and welcomed. Meanwhile I'll turn some old, but uncracked NIP blanks into ? art.
Turn to Safety, Arch Fortiter