1, Wash with vinegar: vinegar is a natural cleaner, which can help to remove the blue substances in fruit juice. Pour the vinegar into the container, then pour the fruit juice into it, stir it evenly and let it stand for a while, then pour out the liquid and rinse it with clear water.

2. Wash with lemon juice: Lemon juice also has a cleaning effect, which can help remove the blue substances in the juice. Pour the lemon juice into the container, then pour the juice into it, stir it evenly, let it stand for a while, then pour out the liquid and rinse it with clear water.

3. Hot water washing: pour the juice into a container, add hot water, and then gently stir with chopsticks or a stirring stick to separate the colors. Then pour out the liquid and rinse it with clear water.

If none of the above methods can solve the problem, you may need to buy new juice again.