Grill

Why the Post Office grilled stamps

Siegel Auction Galleries describes a grill as "an embossed waffle-like pattern in the paper of a stamp that was intended to increase absorption of cancelling ink and improve the adhesive quality of the gum." The worry was that people were washing cancellations off and reusing stamps. Siegel adds that reuse was "nowhere near the perceived threat."

The grill was the idea of Charles F. Steel, a supervisor at the National Bank Note Company. An experimental all-over grill, the A grill, was tested at a small number of post offices in August 1867; its earliest known use is on a 3¢ stamp dated August 13, 1867. The 1869 Pictorial issue used only the G grill, the 1870 issue used H and I grills, and the practice was quietly dropped in the early 1870s.

The grill types

The letters were assigned by William L. Stevenson in articles published from 1913 to 1916, and Scott fully adopted his system in 1926. Grills are told apart by whether the points face up or down, the direction of the ridges and, above all, the size of the grilled area counted in points.

The 1¢ Z grill: two known

The Z grill is the only grill with horizontal ridges, and its earliest known use is on a 2¢ stamp. On the 1¢ Benjamin Franklin of 1868, listed as Scott 85A, only two examples are known. One was donated to the New York Public Library by collector Benjamin K. Miller and is on long-term loan to the Smithsonian National Postal Museum.

The other has a sales history that tracks the top of the US stamp market. Mystic Stamp Company bought it for $935,000 in October 1998, a record for a US stamp at the time, and in 2005 traded it to Bill Gross for the unique Inverted Jenny plate block. At Siegel's June 2024 sale it realized $4,366,000, a new record for a single US stamp. Our Z grill value guide has more on its history.

The B grill

The B grill is almost as elusive. Siegel records four copies, all used and all from a single cover postmarked Mason, Texas, February 17, 1869. Wikipedia reports that one sold for $85,000 in 1993 and about $155,000 at the Zoellner sale in 1998.

How to check a stamp for a grill

• Look at the back under light from a low angle. A grill shows as a grid of tiny raised or sunken dots.
• Count the points across and down the grilled area, then compare with the table above.
• Check the issue. Grills appear on US stamps from 1867 into the 1870s (the last, the J grill, as late as 1875), so a grid on a later stamp is something else.
• Get a certificate before you price anything as a scarce grill. Grill types are separated by a point or two, so an expert opinion matters.