Starting a new series of US auxiliary markings articles on Stamp Smarter. The first two are published for Directory Service and NYC auxiliary markings. You can read them herehttp://stampsmarter.com/Learning/ID...istance.html
Additional articles on customs-related markings, held for postage markings, postage due markings, registration markings, and markings related to stamps being removed before delivery will be forthcoming.
Big thanks to Tony Wawrukiewicz, Thomas Breske, Scott Steward, and others for their efforts.