Rare German OSTROPA Sheet - 1935 Mint Commemorative Sheet of 4

Available only to those attending the OSTROPA Philatelic Exhibition at the Konigsberg Castle in East Prussia, this commemorative sheet is the most famous and desirable commemorative sheet issued by the Third Reich. Well-informed collectors realized that the acidic gum formulation would eventually destroy the paper, and today the most well-preserved examples such as this sheet have the gum carefully removed. This is the preferred way to collect the sheet. (Germany #B68)