I've seen posts on this, but cannot find them now. Can someone put me at ease concerning this? It's not the first time I've seen it, but I will sleep better knowing what is the source. I did a Patman flush with 2-3 quarts and let the car idle for about 2 minutes. If there was any signifigant metallic rubbing, I'd have heard it??? Would'nt the filter have removed anything signifigant? This stuff was small, like a fraction of a grain of salt. What's the dealie?