Erasers are a must have tool for artists and students. They are used to remove blemishes created by pencils but they aren't as simple as they seem. Well first of all you need to know that the lead we currently use in pencils isn't actually lead. Lead is a bit toxic so it was replaced with graphite that is generally harmless. The only downside of using graphite in pencils is that pencil wounds became permanent (it was also mentioned in dangerous school supplies).
Erasers are generally just a piece of rubber. The rubber is usually also bit a harder but still flexible. When you try to erase something with an eraser, it usually takes multiple rubs as the eraser first needs to be softened and turned sticky. Before if softens, the eraser works on loosening the graphite particles from the fibers by scratching against the surface.
The first erasers were actually made of vegetable oil.