before rubber eraser found

Before erasers were invented, people used a rolled up piece of white bread to erase graphite. Some artists still use bread today to lighten charcoal or pastel marks. This changed when Edward Naime, an English engineer invented the eraser in 1770. 
The eraser is called a rubber in some places. The story is that Naime grabbed some rubber instead of bread on accident to erase something and realized its ability.
For this reason it received its name, because it could rub out pencil marks. It was the first practical application found for the substance. Rubber, like bread, was perishable and went bad over time. Charles Goodyear invented the process of vulcanization in 1839 and made rubber erasers common.
Then in 1858, Hymen Lipman patented attaching erasers to the ends of pencils. Later the patent was revoked since it combined two things already invented instead of inventing something new.
Modern erasers come in all types of colors and shapes. They are now made of rubber, vinyl, plastic, gum, or other similar materials.

(source: http://www.omg-facts.com/History/White-bread-was-the-original-pencil-eras/51280#HuxdmyvOWeIrtOLi.99)