There are a few old folk remedies for removing freckles at home with common foods, and they're surprisingly effective. Washing your face in sour milk may not make freckles go away completely, but it will at least lighten their tone. The key ingredient is lactic acid, and there's a higher concentration of lactic acid in sour milk than in milk that hasn't soured. Simply wash with sour milk and water.
A similar method is a sour cream mask. The thick, creamy, taco-topper is applied to the face, where it stays for 10 to 15 minutes to allow the lactic acid to absorb into the skin. It's then washed off with water. It's a good idea to apply moisturizer afterward to prevent dryness.
Another common freckle "cure" is to rub them with lemon juice. The active ingredient in lemon juice is citric acid, which is a natural bleaching agent. In fact, citrus extracts are often used in skin care products because they're a skin "equalizer," or pigment and spot reducer.