If you know a gunsmith or someone who refinishes fireams, they can grit blast with aluminum oxide, 120 and 220 grit, to get to what is called bright metal (no oxidation).
This will take only a few minutes per blade. Then you can polish to the desired finish using previously described methods. I have a blast cabinet and have refinished quite a few guns submerged durung Huricane Rita.
These blade are definately salvageable.
Good luck