We review all best offers. Certain items, such as zeppelins and high denom notes, have very little profit margins leaving very little room for discounting. Offers within 5% of the asking price have the best chance of acceptance.Stamps described with faults are NOT returnable. Stamps generic certificates from The Philatelic Foundation, PSE, or the APS are accepted. NOTE "graded" certificates or "encased" items are not accepted. Proof of the inability of a competent authority to express an opinion is not grounds for return. We use the finest in secure packaging to better protect your items. The item "#567 ON WORDEN FIRST DAY COVER CV $600 BS8817" is in sale since Thursday, March 31, 2016. This item is in the category "Stamps\United States\Covers\FDCs (pre-1951)\Pre-1930". The seller is "billsbargainstamps" and is located in New Milford, New Jersey. This item can be shipped worldwide.