I've removed brown spots successfully from my face by using a lemon.
Take the lemon and apply the lemon to your brown spots. The natural acid in the lemon juice from the lemon will help break down the melanin pigment and reduce the appearance of the brown spots.
It took me a month of applying the lemon to my brown spots to see them fully disappear but if you apply the lemon juice for 30 minutes everyday you should see the brown spots on your face go away.