all about erasers - part 2
Gum erasers (also called ‘art-gum erasers’), like pink and white erasers, are good for clearing large areas of a page. Gum erasers are not as stiff as pink erasers and are preferable for thin papers like drafting vellum or newsprint. Because they are made from a softer, coarser type of rubber, gum erasers are often a bit crumbly (especially if old and dried out). This isn’t an especially bad thing since it’s the little crumbles, called ‘eraser dust’, that actually hold the graphite lifted out of the page. This is why, unlike kneaded erasers, gum erasers won’t become dirty and black over time. They’ll just wear away bit by bit.