The used typewriter drive was started in 1942 in response to the military's need for typewriters. After war production and rationing of steel and rubber forced typewriter factories to convert to weapons factories, the military asked Americans to sell or donate their typewriters to the government. The goal of the campaign was to collect 600,000 typewriters. I couldn't find any information to how many were actually collected, but the actual number was much lower.
The campaign was called Forty-Two Keys to Victory. Celebrities and businesses helped by staging publicity shoots of their own donations. The pictures presented below were collected from various archives. All were produced by the Office of War Information.