I attached them as a second drive on a Linux box and mounted them as Windows filesystems. Linux liked them just fine, and I copied all the files off and burned CD-ROMs for the customers.
This reminds me also back before Windows, several clients had DOS hard disks MS-DOS stopped booting. Couldn't fix them without reformat (which the customers wouldn't allow due to unbacked data). SYSing MS-DOS didn't fix anything, so I SYS'd those suckers with DR-DOS and they worked fine.