These gum based erasers with added silica grit gently abrade themselves as you use them and work better than any other ink erasers on the market. For best results use on better papers, such as that used for resumes and books. Remove inscriptions and library markings without making holes. They also have been found to remove: crayon, dead bugs, stains, light foxing, fingerprints and other such nonsense depending on the paper surface. Price each.