If it's WW II era or 1930s, it would have Zinc reed plates. If it were never played in rain or fog, and kept dry, the reeds migt be easy to restore. Zinc is unstable, and turns into a white powder, which makes the reed plates cause problems. There are a couple of ways to treat this, but the reed will never be quite as good as new. However this kind of reed was very nicely made, and still better than some others, depending on how far corrroded the plate is.