Clock Cleaners (1937)

Clock Cleaners is a 1937 American animated short film produced by Walt Disney Productions and released by RKO Radio Pictures. The cartoon follows Mickey Mouse, Donald Duck, and Goofy working as janitors in a tall clock tower. The film was directed by Ben Sharpsteen and features original music by Paul Smith and Oliver Wallace. The voice cast includes Walt Disney as Mickey, Clarence Nash as Donald, and Pinto Colvig as Goofy.

More at Wikipedia.