At this point I world not worry. there is too much little stuff that can get in the way of a perfect valve face sealing properly.. and as long as the valves were done properly, they will seal after running and cleaning themselves.. LIKELY the stuff will wash out ( into the Bores! ) with the first few Strokes of the engine.. On 'Older Engines' ( not fresh assemblies ) it can be a light rust dusting. I had a rusting problem with my NA Build, as the weather was HOT then COLD.. and the metal parts would sweat.. I ended up with a little Rust on most of the valves.. Bothered me when turning over the engine.. it hissed also A few stroks over the top and she came right to life.. no his problem now.. Cj
