How did reformers expose the living conditions to the public?

To expose and reform corruption in politics.

Explanation:

Since 1892, Steffens worked for the New York Evening Post. He later turned into the distributer of McClure's Magazine, from where he co-built up an analytical style called muckraking, revealing corruption in the American culture, with a special accentuation in New York.

After 1910, Steffens'reporting on corruption bit by bit reduced. Rather, his attention was on the Mexican Revolution. He turned into a heartfelt supporter of the alleged rebels and concentrated increasingly more on the insurgency as the best way to escape capitalism.

To expose and reform corruption in politics.