[3] After the rise of the National Socialist regime in Germany, he moved to Belgrade (then in Yugoslavia), where he opened another gallery and mounted exhibitions, in 1933-1934.
[1] In 1935, he moved to Poland; he spent time in Vilna (Vilnius) and Warsaw, and published articles on art in Yiddish-language periodicals, including Literarishe Bleter.
[5] There he became the leader of the Jewish Society for the Promotion of Fine Arts [pl]; Yiddish: Yidishe gezelshaft tsu farshpreytn kunst), or ZTKSP, a revival of an organization that had been active in Poland before the war.
[7] It mounted some 98 exhibitions in Warsaw, and four exhibitions that were presented throughout Poland – two devoted to the work of individual artists, Rafael Mandelzweig, in 1946, and Lea Grundig, in 1949; and two, in 1948, in honor of the fifth anniversary of the Warsaw Ghetto Uprising, featuring works of Jewish artists who were killed in the Holocaust.
[8] After the dissolution of the ZTKSP, in September 1949, the art works that Sandel and his colleagues had assembled were integrated into the collections of the Jewish Historical Institute, Warsaw.