I would like to add the picture of leaves and abu gosok, as been state in above article.
This is the picture of serumpet which send directly from aceh.
I dont know about species / family name of this leaves.
And this is the picture of Abu Gosok
After asking the blacksmith, they teach me how to create "abu gosok" with the same quality as their "abu gosok". You can create "abu gosok" by burning the coconut fibre till the fibre became white ashes. Before I burn the coconut fibre, I put in the sun to dry. After the coconut fibre became so dry, then I burned it till became abu gosok.