Geee, let me take a guess....I'll bet it's from some blow-by/combustion gas's getting past the rings that accumulate in the crankcase. If you've ever heard of a pcv valve, thats what its for.
As engines get more, and more tired, you'll see way more of this, along with poorer performance.
As engines get more, and more tired, you'll see way more of this, along with poorer performance.