Get the same effect of a double boiler by using:
large pan
a smaller pan
a small tin
marbles or stones
1
Put the small tin in the center of the larger pan, add marbles to the tin (to weight it down) then fill the pan with water and bring to a low boil.
2
Put the smaller pan on the tin and put the item in the smaller pan you want melted, and you have yourself a double boiler!