We just discovered the ultimate Halloween apple dipper: Dulce de leche made in the slow cooker.
Remove the labels from two cans of sweetened condensed milk. Make sure there are no dents in the cans.
Fill crockpot with water. Place the cans on their side inside. There must be at least one inch of water covering the top of the cans. Keep your eye on through cooking to make sure they are fully submerged.
Turn crockpot on low and cook the cans in water for 8 hours.
Let the cans cool completely. Never open the cans when they are hot, because they may explode.