Wow! Keep us posted. It's hard to know what each individual here is going to run up against. A little heat on that plug would probably break it loose, but not everyone has a torch.
I wish others with more experience would chime in. Seems to me one of those big cans of carb cleaner with the plastic straw and enough compressed cleaner, then change the oil right away may work (down the passage). I hate to suggest stuff I havent tried myself or could be missing possible ramifications.
