The Benjamin Franklin Z-Grill is a 1-cent postage stamp issued by the United States Postal Service in 1868 depicting Benjamin Franklin.
The Benjamin Franlink Z-Grill Stamp has the unique feature that there are tiny squares embossed into the paper in the back of the stamp to absorb the ink. This is to prevent people from cheating the postal system by washing out the cancellation marks. The use of grills was not found to be practical and they were soon discontinued.
There are currently only two known 1-cent 1868 Z-Grills. One is owned by the New York Public Library as part of the Benjamin Miller Collection. And only a single Benjamin Franklin Z-Grill is in private hands.
In 1998, Mr. Robert Zoellner’s complete USA collection was sent to auction, and Donald Sundman, president of the Mystic Stamp Company, acquired The Benjamin Franklin Z-Grill for $935,000.
Later, in late October 2005, Sundman traded this Z Grill to financier Bill Gross for a block of four Inverted Jenny stamps worth nearly $3 million. After completing this trade Gross became the owner of the only complete collection of U.S. 19th century stamps.