Postage stamp reuse

In many countries, such as the United States, reuse of used stamps, whether cancelled or not, is illegal.

In both cases the theory was the same; the ink of the printed design would not soak into the varnish, so that in the washing process the design would tend to flake off, forming a telltale pattern on the washed stamp.

The United States also coated a few of their $1 revenue stamps with varnish around the turn of the 20th century.

More unusual methods have included tearing or slicing the stamp, but this is a slower process and can easily damage the contents, and was only occasionally used.

An example is 19th century Afghanistan, where cancellation involved the removal of part of the stamp rather than applying ink or other surface marking.