I used modelling chocolate in a sort of reverse Bas Relief method, then covered the whole cake in fondant, which was airbrushed silver. You can just make out a little spot of red at the bottom of the photo … This marked the special hiding place of an actual dime (wrapped in wax paper, then plastic wrap, before being popped between the layers). This was a farewell gift from the bar staff to a patron who always tipped them in dimes.