Other Stamp Varieties
US Stamps With Certs
As with coins, baseball cards, comic books, and even rock posters, in recent years some stamp collectors have started submitting their stamps to grading agencies for "expertising." A few of the best-known organizations that issue certs for stamps include Professional Stamp Experts, the Philatelic Foundation, and the American Philatelic Society. Some sellers list their stamps for sale with an existing cert, while others will offer...