The phrase "ash heap of history",[n 1] is a derogatory metaphoric reference to oblivion of things no longer relevant.[1]
In 1887 the English essayist Augustine Birrell (1850–1933) coined the term in his series of essays, "Obiter Dicta": that great dust heap called 'history.' [1]
A notable usage was that of the Russian Bolshevik Leon Trotsky referring to the Mensheviks: "Go where you belong from now on – into the dustbin of history!" as the Menshevik faction walked out of the All-Russian Congress of Soviets on 25 October 1917 in Petrograd.[2][3][4][5][n 2]
In a speech to the British House of Commons, on 8 June 1982, U.S. President Ronald Reagan later responded that "freedom and democracy will leave Marxism and Leninism on the ash heap of history".[6]
Similar expressions are "sink into oblivion", "fall into oblivion", "drop off radar", "fall off radar". Lethe, in Greek mythology, a river of oblivion, gave rise to the Russian expression of the same kind: "sink into Lethe" (кануть в лету).