what metal doesn't cause the acid to change color?

I find a lot of silver, sometimes unmarked, and have never acid tested. If the piece is something that is all silver (no wood or mixed metals), then you can test specific gravity and that does absolutely no damage. You just need a decent scale and a big pot of water. You can find instructions on the internet.

Back to the original post, were these spoons actually marked sterling?? I would be very surprised - can you post a pic of the mark if you haven't trashed the spoons yet?

 

The ones I just saw were chrome, but there was a company making souvenir ware back when whose name was Sterling. They might well be marked that, but I think those were late enough to be Taiwanese.

 

I wonder if that is just an urban myth? Has anyone ever seen an example first-hand to back it up?

 

I have at least one souvenir charm with the mark on it that seems to be pewter, so...yep. It came from the Mark Twain House in Hartford CT. I don't know for sure about spoons, but the charms have turned up.