If you want to make your own dulce de leche the simplest way is to boil a can of sweetened condensed milk. Submerge the can of condensed milk (label removed) in a pot of water, covering the can completely. Bring the pot of water to a boil, reduce heat and simmer for 2-3 hours. Top up the water as needed to make sure the can is always covered. For a lighter coloured caramel boil 2 hours and for a darker caramel boil 3 hours.  Let the can cool completely before opening as the metal will be extremely hot.