ERASER

Before erasers, wax tablets were used. Pieces of rough stone such as sandstone or pumice or breadcrumbs were used to remove small errors from documents written on parchment or papyrus. In 1770, English engineer Edward Nairne developed the first commercial eraser.

In 1839, Charles Goodyear discovered the process of vulcanization, a method that would polymerize rubber, making it durable. On March 30, 1858, Hymen Lipman of Philadelphia received the first patent for applying an eraser to the end of a pencil, which was later invalidated.

Erasers can be free-standing blocks or caps mounted on the end of a pencil. Many wooden pencils are made with built-in erasers. The erasers supplied with some ballpoint pens and permanent markers are intended to erase only the ink of the writing instrument for which they were created.