I had an interesting read about check washing, a process of removing pen ink from a check that’s already filled out, then re-writing the new amount of money and the recepient on the check.
In the experiment, 4 pens were used for testing — a gel pen, a generic cheap pen, a pen with a felt tip and a roller pen. Two solvents were also used, an 91% isoprophyl alcohol solution which is polar and nail polish remover, a non-polar solvent. If you still remember your Chemistry subject, polar substances only dissolve in polar solvents and non-polar substances only dissolve in non-polar solvent. Different pen inks contain different substances; this experiment tested several combinations to dissolve each kind of ink.
The result is very interesting: If you want to protect yourself from check washing you should use gel pen because gel pen ink is the most difficult ink to wash out from checks. However it’s not guaranteed as there might be a method to wash gel inks soon. For more information and tips you can read the conclusion of the experiment.
Links:
Celtickane.com projects: Check Washing Experiment [ via Digg ]