Iv got a Lee production pot iv thats given good service for many years but is starting to drip badly from the spout, to the point where more lead is going on the bench than in the moulds. Its easy enough to clean the sides and bottom of the pot when its empty but i cant seem to be able to get to the sealing face where the valve rod sits to stop the flow. Anyone know of a cleaning substance that will dissolve hard lead dross?