1 can sweetened, condensed milk
Pierce two holes in top of can of milk.
Place can in small saucepan and add enough water to reach two thirds of the way up the can.
Bring water to boil and continue boiling on medium high heat for 1 1/2 – 2 hours, adding water as needed to keep it at the halfway mark.
To test, pour a little onto a plate. It should be light brown or caramel.