Need help with damascus refurb.

[beckerhead]

I have another thread in Maint. & Tinkering and was advised to ask here as well. I am working over a number of knives for a friend, and 2 are damascus folders, 1 being a nice little limited run canoe that is his favorite deer knife. I need to clean these significantly rusted and corroded blades, but am skittish about removing the etch by sanding/polishing, as these are assembled pinned folders that I have neither the means, nor experience to break down and reassemble. So, all that blabbing to say, that I need either a non- etch damaging cleaning medium/technique, or a way to re-etch an assembled folder.