Preheat oven to 400 degrees F (200 degrees C). Grease 54 muffin cups or line with paper muffin liners.
Beat bran cereal, buttermilk, flour, sugar, fruit cocktail, vegetable oil, eggs, cinnamon, and salt together in a bowl with an electric mixer on medium speed until batter is blended, about 2 minutes. Spoon batter into prepared muffin cups, filling each about 2/3 full.
Bake in the preheated oven until golden and set, 16 to 18 minutes.
