Technically, it's off topic for this section of Photrio, but digital post can save a lot of stuff you couldn't get even a decent print from. Otherwise, the question is how hard a cut you can get on a minus-blue filter to try for 00 or even 000 contrast level. A tri-color green filter should give the least contrast multigrade will give.
Of course, there is another, completely analog method: bleaching.
Two options here. Farmer's Reducer can be mixed in a way that bleaches proportionally (IIRC), so you could bleach by inspection with that, or you could use a rehalogenating bleach (C-41 bleach that doesn't include fixer will work for this) and redevelop for a shorter time. This can be redone, within limits, to adjust the final contrast. It won't do anything good for grain, but it might make printable out of unprintable...