The act of scraping, scratching, or shaving the surface of a written in- strument, for the purpose of removing certain letters or words from it. It is to be distinguished from ” obliteration ,” as the latter word properly denotes the crossing out of a word or letter by drawing a line through it with ink. But the two expressions are often used interchangeably . See Penny v. Corwithe, 18 Johns. (N. Y.) 499.