Eraser

An eraser, (also called a rubber outside of U.S., from the material first used) is an article of stationery that is used for removing writing from paper. Erasers have a rubbery consistency and come in a variety of shapes, sizes and colours. Some pencils have an eraser on one end. Less expensive erasers are made from synthetic rubber, but more expensive or specialized erasers are vinyl, plastic, or gum-like materials. Cheaper erasers can be made out of synthetic soy-based gum.

Erasers were initially made for pencil markings, but more abrasive ink erasers were later introduced. The term is also used for things that remove writing from chalkboards and whiteboards.

Before rubber erasers, tablets of wax were used to erase lead or charcoal marks from paper. Bits of rough stone such as sandstone or pumice were used to remove small errors from parchment or papyrus documents written in ink. Crustless bread was used as an eraser in the past; a Meiji-era (1868-1912) Tokyo student said: "Bread erasers were used in place of rubber erasers, and so they would give them to us with no restriction on amount. So we thought nothing of taking these and eating a firm part to at least slightly satisfy our hunger."

In 1770 English engineer Edward Nairne is reported to have developed the first widely marketed rubber eraser, for an inventions competition. Until that time the material was known as gum elastic or by its Native American name (via French) caoutchouc. Nairne sold natural rubber erasers for the high price of three shillings per half-inch cube. According to Nairne, he inadvertently picked up a piece of rubber instead of breadcrumbs, discovered rubber's erasing properties, and began selling rubber erasers. The invention was described by Joseph Priestley on April 15, 1770, in a footnote: "I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black-lead-pencil. ... It is sold by Mr. Nairne, Mathematical Instrument-Maker, opposite the Royal-Exchange." In 1770 the word rubber was in general use for any object used for rubbing; the word became attached to the new material sometime between 1770 and 1778.

...
Wikipedia