But what's the blue part of the rubber for?

Everyone knows the two-colored gum, with its pink side and its blue side. For years, a popular belief circulated: the blue side would be used to erase the pen. Who has never stumbled upon his notebook, hoping to remove an ink error, and finally end up with a hole leaf?

But then, what is the real use of this blue part?

The myth of the pen: why did this belief take root?

For generations, the idea that the blue part erases the pen has been transmitted, probably because of its harder and abrasive texture. Many have tried to test this theory... with more holes in their notebook than success.

In fact, this face of the gum is not designed for pen inks, which penetrate the paper instead of remaining on the surface like the pencil. Rotting harder will only damage the leaf without actually erasing the ink.

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