For both coins I followed the same procedure of one tablespoon of sodium thiosulphate disolved into 100 ml of boiling water. I submerged each coin in the hot solution for about 30 minutes to dissolve the horn silver. After gently cleaning the coin with a toothpick, i repeated a second time.
That's all i did for the coin in the second post. For the first coin, I also
had to do long soaks in lemon juice to get some very hard encrustations off.
I think they would both improve with more cleaning but I'm very happy with their appearance in hand and plan on leaving well enough alone.