To prepare the caramel: Remove the labels from the sweetened condensed milk cans and wash the cans. Place a sheet of parchment paper in your slow cooker to avoid rust rings.
Position the cans on the parchment paper and fill the slow cooker with water until the cans are covered by about two inches of water, cover with lid. Set the slow cooker to the low heat setting and cook for eight hours.
After the cooking time, turn off the slow cooker and let the cans sit inside for four hours. Once the cans are cool enough to handle without burning yourself, open the cans. Opening the cans before cooling could cause the caramel to splatter. Proceed with caution as the contents are pressurized. Spoon into a bowl and enjoy.
**** DO NOT open cans until cooled to room temperature