Cover from Nürnberg, Germany, to Avila, with censor mark Heller A144.1. Postmark dated on December 12, 1936. On the back Poste Restante arrival mark dated on December 14, 1936, handwritten note "No está en esta oficina" (Not found in this office) and rare censor mark "Gobierno del Estado Español - Oficina de Prensa y Propaganda".
Stampless cover from Illescas (Toledo) to Cördoba, with mark of Illescas Town Council for lack of stamps and postmark dated on November 24, 1936. On the back info of the sender: Lonrenzo Prats, Artillería Pesada Nº 1, 4a Batería Obuses 15,5, Columna Madrid, Carabanchel Alto. Córdoba arrival backstamp dated on November 30, 1936.
Callús unlisted censor mark, not published by Heller, "Comité d'Enllaç Antifeixista de la Comarca Manresa-Berga" on cover from Callús to Los Angeles, USA. Callús postmark dated on August 1936 and another censor mark from Barcelona Heller RB3.11. Very rare.
Cover franked with 30c Edifl 687 and Villacarrillo postmark dated on August 13, 1936, sent to Celso Bueno y Bueno in the Cathedral Prison of Jaén. Arrival Jaén postmark on the back of the same date. The Cathedral of Jaén was a prison from August 3, 1936 to November 7, 1937. Very rare.
Cover from the front to Valencia, with postmark from Polán (Toledo) and franchise mark "Milicias Populares Antifascistas / 1a Compa 1er Bon / Regto Uribarry Nº 1" on the front and the back. Arrival backstamp. Extremely rare.
Cover from Casasbuenas (Toledo) to Valencia, with red franchise mark "[Partido Comunis]ta - Casasbuenas (Toledo)" and unlisted censor mark "Comité de Milicias y Defensa / de la ciudad / Casasbuenas (Toledo)" on the front and the back. Valencia arrival backstamp fo Dec 4, 1936. Very rare.
Cover from Courbevoie to Santander, postmarked on July 18, 1936. Handwritten note "a su procedencia" (return to sender) and blue arrow marking the town where the cover had to be returned to. On the back, very rare Irun censor mark Heller RI3.1 with handwritten note "se ausentó" (they left the town).
Air Mail cover from Madrid to France franked with Edifil 688 (2) and postmark Sucursal No 8, Madrid, dated 21 Dic 1936. Valencia censor mark Heller RV2.1c on both sides of the cover. French transit marks on the back.