There is a man in Katowice who has spent four years putting fabulous old recordings of 78s from Poland onto youtube. His online name is jurek46pink - if you clink that link, you can subscribe to his channel. He has an amazing collection, not only of recordings, but of photographs and memorabilia, and for quite some time he shared it all quite liberally with the online community.
When he discovered that people had started copying his materials without permission, he became more cautious, but luckily he hasn't packed up and left town! You can hear the old Polish tangos on his channel and marvel at how much he knows about the period.
He says he will help me with my 'M'ken nisht tsvingen tsu keyn libe' request. I'll let you know when it's posted.