When the Canadian government guarantees the purity of the $5.00 Maple leaf coin 
as being .9999 % pure,how can you be sure everybody else's compares as well?.As 
for suspending in DW,it isn't necessary the whole coin be submersed, they / it 
can be hung with alligator clips.I find that about 1/4" of the coin in the DW 
works very well,AND,there is enough silver in the coins to make at least a 
zillion gallons of CS.
Harold