Check washing is a somewhat unsophisticated but often effective form of fraud in which a legitimate check's information is erased chemically or electronically, allowing a criminal to rewrite the amount of the check and the name of the payee. While there may be some defenses, such as electronic inks and hidden watermarks, to guard against such fraud, the technique works because many recipients accept the check at face value due to the legitimacy of the signature. Because rudimentary methods can easily damage a paper check, however, many con artists ruin more checks than they can cash.
The washing process is not especially difficult, although the results can vary widely. In a typical operation, a legitimate check is prepared by placing a protective seal over the signature line. This could be a low adhesive tape or sticker. The check is then held with tongs and placed in a pan that usually contains acetone (nail polish remover), paint thinner, or bleach. The chemical dissolves many types of ink found in standard ballpoint pens. Once the ink from the check has dissolved completely, the check is hung up to air dry. The result, ideally, is a signed blank check, which the con artist can rewrite to suit his or her needs.
One popular method of obtaining legitimate checks for check washing is to drive through neighborhoods and secretly inspect outgoing mail left in curbside mailboxes. Payroll checks and bill payments are especially popular targets. Sophisticated con artists have been known to carry portable computers, laminating machines, scanners, and high-end printers in their vehicles that allow them to create false identifications in order to cash batches of washed checks.
The main problem with this type of fraud is creating a truly blank check. The ink contained in a standard blue ballpoint pen is easily removed with acetone, but black ink can be problematic. Experts say gel pens with black ink provide the best protection against check washing, since the gel ink resists chemical stripping and contains pigments that permeate the fibers of the check itself. A washed check cannot be used if it looks altered or bleached out.
One way that people can protect themselves against this type of fraud is to switch from blue to black ink when writing checks, and to use a gel pen whenever possible. Additional safety measures include taking bills and other outgoing mail containing checks directly to a post office or public mailbox. A personal mailbox with a lock may also discourage outsiders from stealing the mail, but this type of mailbox may not be usable for outgoing letters. Many experts recommend that people invest in checks containing anti-fraud elements such as electronic inks, hidden watermarks, or microprinted lines that cannot be photocopied or scanned clearly.