It's possible to leach the salts from the water by flooding it with
fresh water often.
If you can afford the water it's worth a try. We are talking laying
down the equivalent of a foot of rain a few times with a few days
drainage in between,
But it's also likely that having waited this long that your plants are
goners.
Ericacious plants are not salt tolerant at all. Azaleas are in that
group.
Similar plants will lead you into the same kind of heartbreak.