I could use some advise from anyone who has experience with metal artifacts and might know how to deal with rust. Last month I worked on several early homestead sites in Kansas and I'm processing what seems like millions of pieces of metal collected from both the surface and from excavated units that have suffered from at least 100 years of regular flooding. Some of the nails and other pieces have rusted together into massive balls and some of the nails are so badly rusted they are not diagnostic at all. The Senior Archaeologist wants me to find a way to remove the rust, but I'm concerned that many of these nails, etc are nothing but rust now. And I'm also concerned about conservation, obviously.  What do ya'll think?