Many people visiting Aranmula, and  write about their experience there. We found a blog, http://sankriti.blogspot.com/ and here is the write up about Aranmula Kannadi in his own words. ( Info and photo courtesy: http://sankriti.blogspot.com/ )
Aranmula is also famous for its traditional metallic mirrors known as Aranmula Kannadi. It is made of copper tin alloy and the ratio is a closely guarded secret.This is a unique art & handed down from generation to generation. Presently only five families are involved in this art in Aranmula and these families hold a patent. We visited one such family and studied the process of manufacture of this unique and beautiful mirror. See pics below:
