Over 95% of grills are either E or F grills. The A, B, C, and D grills had proved to be unsatisfactory, mostly due to their presence on the stamp making the stamp difficult to separate. The Z grill did not have that problem but for whatever reason it was printed in very limited quantities. The F grill was the last of the grills. Grilling was expensive and it was increasingly seen that there was no need for it. Grilling did have a benefit; it helped the National Banknote Company win the contract. For more on grills see types of grills.

The last day stamps were grilled was March 25th,1869.