Tough call. The plants themselves (stems, crown, roots) will still be alive, but they will have less energy to draw on over the winter without the leaves. I'd cut off the yucky leaves and try overwintering them, they might make it.

When I bring my geraniums in for the winter, I dig them up, shake off the excess dirt, trim back the feeder roots and the top by about 1/2. I do this because they are too big otherwise and to help get rid of some insect eggs in the soil or on the plant. I then repot them and water with an inseticidal soap mix. I used to store mine in the garage for the winter, we kept it at just above freezing. I withheld water until about Feb. when I wanted them to actively start growing again. Hope this helps. Marg