The traditional erasing method involved the use of a special typewriter eraser made of hard rubber that contained an abrasive material. Some were thin, flat disks, pink or gray, approximately 2 inches (51 mm) in diameter by ⅛ inch (3.2 mm) thick, with a brush attached from the center, while others looked like pink pencils, with a sharpenable eraser at the “lead” end and a stiff nylon brush at the other end. Either way, these tools made possible erasure of individual typed letters. Business letters were typed on heavyweight, high-rag-content bond paper, not merely to provide a luxurious appearance, but also to stand up to erasure.
Typewriter eraser brushes were necessary for clearing eraser crumbs and paper dust, and using the brush properly was an important element of typewriting skill; if erasure detritus fell into the typewriter, a small buildup could cause the typebars to jam in their narrow supporting grooves.
Correction Fluid
In the 1950s and 1960s, correction fluid made its appearance, under brand names such as Liquid Paper, Wite-Out and Tipp-Ex; it was invented by Bette Nesmith Graham. Correction fluid was a kind of opaque, white, fast-drying paint that produced a fresh white surface onto which, when dry, a correction could be retyped. However, when held to the light, the covered-up characters were visible, as was the patch of dry correction fluid (which was never perfectly flat, and frequently not a perfect match for the color, texture, and luster of the surrounding paper). The standard trick for solving this problem was photocopying the corrected page, but this was possible only with high quality photocopiers.
A different fluid was available for correcting stencils. It sealed up the stencil ready for retyping but did not attempt to color match.
Correction Paper
Correction paper, or correction film, its plastic based equivalent, is a tab of plastic with one side coated with white correction material. It is used to correct typing errors made when using a typewriter. When inserted between the paper and the ribbon, the impression of the typebar presses the shape of the character into the film, which prints the white correction material onto the paper, hiding the erroneous character and preparing the document for the correct character.