The 80-85% recovery for unmarked silver may be true at the current market level. That percentage would go up the higher the silver price level goes. It would also go way down if silver returned to the 5.00 level. The cost of refining would remain the same no matter what the value of the silver. Consider the gold market, the cost of refining gold (ie 14kt to pure gold) is similar to that of refining silver. Since gold has a value 45 times higher than silver, the cost of refining gold is a much much smaller percentage of the actual gold value. If (and I believe it will someday) silver goes to the 50.00 level, the cost of refining unmarked and sterling silver should be under 5% of the silver value.