Twelve Cent Clay Bank Notes
The Secret Mark

Scott 151P3 - National Printing
No Secret Mark - Proof on India

Scott 162P4 - Continental Printing
With Secret Mark- Proof on Card

Closeup of the Secret Mark

Scott 140 & Scott 151 - No Secret Mark
National Printing - There is no added dash of color to the balls in the numeral "2"

Scott 160 - With Secret mark
Continental Printing - There is an added dash of color to the balls in the numeral "2"

Follow these steps in the identification of your twelve cent Bank Note:

There is no need to the check paper type on this stamp, all 12¢ Bank Notes were printed on the "hard white" paper, except the ultra-rare special printing by the American Bank Note Company, Scott 198, which was printed on the soft porous paper. You must still check for the "secret" mark. If it does not have the secret mark it is a National Bank Note printing. If it has the secret mark it is the Continental Bank Note printing, Scott 162.

If the stamp was printed by the National Bank Note Company, check for a grill to determine the Scott number. If the stamp has a grill, it may be the rare Scott 140. If it does not have a grill it is Scott 151. Care must be taken when authenticating the grill. Many fake grills have been added over the years in an attempt to increase the value of the stamp, although this stamp is so rare that purchasing this stamp without certification is sheer folly.

Watch for re-perforation (to fake a more well-centered stamp), for re-gumming (a major problem with the Bank Notes), and even for bleaching of the cancellation (to remove the cancel). Unused copies carry a substantial premium over the used stamp.

The Special Printings, Scott 173 and Scott 198, are mentioned here merely for completeness. Only 282 copies, total, of Scott 173 and Scott 198 were sold, and they were never issued for postal use, rather for collectors only. We occasionally see uncertified copies of these stamps offered for sale at ridiculously low prices. You can rest assured that the stamp being offered is not genuine. These stamps are so rare, only 135 copies are known, they seldom come up for sale except in the sale of a major U.S. Collection.