ok i was doing some work to a spare rocker cover over the weekend,(grinding down the lines on the cover) getting it ready to paint, when i had a bit of a problem.... here's my work so far. i had tapped up all the plug holes and pcv hole was blocked when my old man went and took them off to have a look at it and afterwards i found some tiny metal dust particles in and around the plug holes ad pcv valve hole, i intended to washer the rocker cover very well before painting it my question is will the rocker now be safe to use, if the metal dust has gotten into the inner surfaces will the cover be safe to use once cleanedas i don't want the metal articles mixing with the oil, will cleaning the cover be enough to prevent any damage being caused to the engine whenits in use???