Craig Smith from the School of Film/Video at California Institute of the Arts undertook a huge digitisation project to archive rolls of film and tape containing sound effects from the 1930s to 1950s from Hollywood, and shared them on freesound.org under a Creative Commons 0 license. This is a generous and valuable undertaking to preserve some of our global cultural heritage, and it is wonderful that the material has been made available to all. More details of the project are included in the linked blog posts below.
Thanks for the heads up Tim.