Can you tell me anything more? I'm just a diver that has been lucky enough to find a few things.... I've also found a cannon ball that maybe you guys could help me with. I'll upload a few pics when I get the chance. Thank you!
I've seen many cannons and ship parts around Fort Fisher area North Carolina that had a preservation TANK filled with salt water that was changed every so often till the fresh water got rid of most of the salt destruction. IT DOES take a very long time but its about the best you can do. I've seen some electrical probes put into the water at that place but I wasn't sure what that helps with.
Works for gold, silver, bronze, silver/nickel coins. Another process used by shipwreck hunters for artifacts is called electrolysis. Some good threads already on the subject in shipwreck forum. It is done with direct current to 2 electrodes (one is holding your encrusted find) in water with a lot of salt added. One electrode can be your find with copper wire bent to hold it. This tends to eventually start to dissolve copper wire. Don't attach a clip because it will disappear in a hurry. Of the most durable of metals, can work for the other electrode, stainless steel is on top of high end. Attach your copper wire to stainless steel object and lower down in salt solution. Depending on how encrusted your object is, salt solution could become depleted and need fresh solution added to replace it.
Any plug in AC/DC converter device will work for the direct current. The one I still have, came from Radio Shack years ago.