What is the blue part of the eraser used for?

Legend has it that this blue part has the ability to erase ink .

We all used this type of eraser / eraser right?

And there's a legend that says, the blue part of the eraser is capable of effectively removing ballpoint ink, and the brown part is for erasing the pencil. Certainly everyone knew about it, but were disappointed because it was true that it erased the ink, but then left a hole in the hole in the hole.

We are completely wrong.

The blue part is actually to remove pencil marks that are painted on the surface of thick and rough paper , which explains why the green part of the eraser is also a bit rough. When drawing on these papers, normal bleaching will require more force to remove pencil marks.

It is unclear why there is a rumor that the blue part erases ink, probably because of its color. At least after reading this article, students will not have to bear the torn paper when trying to erase the ink / ballpoint pen.