A well-preserved set of US Second World War posters will be auctioned later this year.

The 72 propaganda posters come from the collection of Vernon Rader, the retired Procter & Gamble art director, who bought them for less than $50 in the 1960s.

 The items, which bear slogans such as "Loose lips bring down ships" and "Factory fires help the Japs", will likely be popular with historians, art lovers and militaria investors alike at the Humler & Nolan auction on June 4.

 The posters were produced between 1942 and 1945 but never used, as Rader explains.

"They've never seen the light of day. These posters were folded before they left the printing plant, laid flat in a box and never displayed. That's why their colours look so vivid," he said.

A Rockwell poster from 1943

Rader added that the US government produced the posters for use in public places such as post offices, factory bulletin boards and barber shops.

A number of the works were designed by famed artist Norman Rockwell. Estimates for the posters range from $200 to $3,000 each.