[citation needed] It was during his time as consul in neutral Switzerland that Castellanos was approached by a Transylvanian-born Jewish businessman named György Mandl who reiterated to him the grave situation in which he, his family, and countless of his coreligionists found themselves.

[citation needed] Following a close call with the Gestapo in which the faux position and papers saved the family (who now bore the Italianate name of Mantello) from being sent to Auschwitz, Mandl (with Castellanos's consent) proceeded to secretly issue at least 13,000 "certificates of Salvadoran citizenship" to Central European Jews (principally through the Swiss Consular Office of Carl Lutz).

[citation needed] The documents granted the bearers the right to seek and receive the protection of the International Red Cross and, eventually, of the Swiss Consul in Budapest; these guarantees, in effect, saved thousands of "Salvadorans" of Bulgarian, Czechoslovakian, Hungarian, Polish, and Romanian extraction from Nazi depredations.

[citation needed] In 1995 President Bill Clinton, in a letter to the Anti-Defamation League, paid tribute to Colonel Castellanos and other members of the Salvadoran diplomatic corps, for their efforts in saving thousands from Nazi extermination.

[citation needed] After the Israeli Foreign Ministry and the Jewish Community of El Salvador have both applied to Israel's Holocaust Martyrs' and Heroes' Remembrance Authority", José Arturo Castellanos Contreras was recognized with the title of "Righteous Among the Nations" by Yad Vashem in 2010.