Dùng nước cốt chanh. Dùng buttermilk. Dùng mật ong và sữa chua. Dùng giấm táo. Dùng lô hội. Dùng dầu thầu dầu. Dùng bột gỗ đàn hương.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Lemon juice contains citric acid, which can help to bleach age spots. Simply dab a little fresh lemon juice directly onto the sunspot and leave to sit for 30 minutes before rinsing off. Do this twice a day and you should start to see results in a month or two.  Lemon juice makes your skin more sensitive to sunlight (and could make the age spot worse) so never leave lemon juice on your skin if you're going outside. If you have very sensitive skin, the lemon juice might be irritating on your skin,