My husband and I are restoring a Fisher XL that has nickel-plated doors. The previous owner stored the stove in a barn and the nickel plating is pretty corroded in places. I cleaned it with baking soda and then with a salt/lime juice mixture that I found online. It helped, but there are still some spots that are pretty bad. We're afraid to sandblast it for fear it will damage the nickel. Any suggestions?