I haven't used Digital Ice on a flatbed scanner, but on my film scanner it works marvels - small specks of dust, hairs, etc. gone with no appreciable effect on the rest of the image (e.g. softness, etc.) even if you zoom right in. I have no idea how they do that. I would recommend a DI scanner to anyone.
BUT if the flatbed works anything like the film scanner DI won't take care of the level of damage you're talking about - or at least, if it has a setting on which it will then you're likely to start losing image detail. So you're going to have to learn some restoration the hard way

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