Eraser is a device for removing marks from paper or some other surface. Pencil erasers remove pencil marks by rubbing. Most pencil erasers are made of soft rubber that crumbles gradually when used. A compound called gum eraser crumbles more easily and is used on surfaces easily damaged by rubbing. Ink erasers contain powdered pumice or a similar material that removes some of the paper, exposing a clean surface. Some inks can be removed with erasing fluids. Erasing fluids may consist of a bleach called hypochlorite and an acid applied in succession, and then removed by blotting.
Chalkboard erasers remove chalk marks by wiping. Most such erasers are made of strips of felt attached to a stiff backing. Erasers for dry-erase boards are made of nylon or other synthetic fibers. Dry-erase boards are nonporous, and special markers are used to write or draw on them. The marks become a dust that is attracted to the eraser.
