Oh man they can be trouble. I left the oil cap on the valve cover off and they moved in over last winter. Had to pull the cover and clean the top of the head inbetween rocker arms and push rods hoping not too much fell down to the oil pan. On another car I left the carb off overnight and found crap in the manifold the next morning. Had to pull the manifold in fear of sucking in a nut shell or something. The motherhood thing would make me pause, but other than that, the ends justify the means!
Rick in VA