I stumbled across an interesting post over at Arcane Radio Trivia where the author discovered an old Home Recording Acetate, in bad shape, but still intact enough to recover some information.
From around or before 1940, these “phonograms” were used to record programs from the radio or from an attached microphone at home. This one had a flimsy paper core which apparently didn’t hold up well to the test of time, but Arcane Radio Trivia managed to grab 1:57 of audio from it.
Thanks for the link. That one took a lot of work! I’ve ripped over 100 others. You can see my master list here: http://tenwatts.blogspot.com/p/an-index-of-acetates.html