Will Dr Pepper clean a penny?

Well both have acid. Sprite has citric acid and Pepsi Cola has phosphoric acid. However cola also has caramel, which is the brown colouring, so this may make the cleaned penny look a bit browner. I don't know the precise proportions of acids in the two drinks, as the makers keep these secret, so the best way to find your answer would be to do an experiment with two equally dirty coins.