Article in English: Lemon juice contains an acid that may help break down melanin pigment and thus reduce the appearance of spots within a month or two. Vitamin C in lemons may directly bleach the skin as well. Cut a lemon into slices and place the slices directly on the brown spots. Leave it on for about 30 minutes and then rinse off with running water. Squeeze the juice of one lemon into a bowl and add 2-4 tablespoons of sugar, slowly adding the sugar until it combines with the lemon juice to make a sort of paste.  Apply the mixture to each brown spot with a brush or a cotton swab. Leave the paste on for about half an hour and then rinse it off with cool water. This paste may dry your skin, so be sure to apply a moisturizer after every treatment. Squeeze the juice of one lemon into a bowl and add up to 2 tablespoons of sugar (depending on how much juice the lemon had) and two tablespoons of honey, making a goopy paste.  Apply the mixture to each brown spot with a brush or a cotton swab. Leave it on for a half hour and then rinse it off with cool water. The honey provides moisture to protect your skin from over-drying.

Summary in Vietnamese:
Thoa nước cốt chanh trực tiếp lên các đốm nâu. Sử dụng nước cốt chanh trộn đường. Trộn hỗn hợp bột nhão bằng mật ong, đường và nước cốt chanh.