Washer dropped in Distributor/oil pump hole

Drain oil pan, it may be visible thru hole or flexible magnet?
You could drag a strong magnet along bottom of pan to get it closer to hole?
Good suggestion ...Ill try that , but first will try using an endoscope camera setup which i'll have to borrow from a friend...that should hopefully detect it. remember,... i said that the both the distributor AND the oil pump drive were out when it fell in so it may have ended up in the oil pan???