The U.S. govt tries to keep in advance of improvements that make counterfeiting simpler by incorporating refined security measures to bills. I take advantage of the normal or collector grading described in Amassing Confederate Paper Money in addition to 3rd party grading with my modifying stickers indicating excellent notes – https://keeganwzumb.nizarblog.com/33980471/high-quality-copyright-money-no-further-a-mystery