If the expired ink has not deteriorated, there are several ways to reuse it.

If it is black or dark ink, you can use it to practice calligraphy. Because calligraphy does not require as much ink as writing, even if the color changes a little, it will not have much impact.

It can also be used for painting, such as ink painting or some abstract painting. In these cases, expired ink may produce unique color effects.

However, if the ink has deteriorated, such as having an odor, precipitation or mold, it is not recommended to reuse it, because it may damage the writing and painting tools.