The audio processing software techniques must have taken a big leap forward recently.

I just bought this 4 cd box set, Cajun Capers - Cajun Music 1928 - 1954, by Proper Records, and they cleaned up a LOT of background static. You can still hear some, but, I can hear vocals very clearly, with some resonant timbre, and the instruments are fairly clear too, not hazing out in a background of hiss.

On some songs there is a slight bit of dullness as they ended up scraping a bit of the highs out of the vocals and instruments, but its not that noticable. Given the trade-offs, its a good deal.