In the first sauce pan, combine 1/2 the can of condensed milk and the 2 cups of peanut butter chips with a pinch of sea salt. In the second sauce pan, combine the rest of the condensed milk and the 2 cups of chocolate chips, with a pinch of salt. Heat both sauce pans over medium-low heat at the same time. Stirring occasionally. Watch closely to make sure it doesn’t burn. Heat until smooth and creamy.