I like those coins quite a bit. Have several in my collection. A few answers:
1) I believe it depends on denomination. Check out Numista pages such as
https://en.numista.com/catalogue/pieces590.html. In the comments section re: this 10 Nuevo Pesos coin, there is a mention of... "The inner part consists of 5.604 g of .925 silver." I'm not sure how it was determined. Perhaps someone removed the ring -- it's on there tight -- and weighed it? Or maybe the mint provided that?
2) Don't think it's easy to remove but I've seen these coins offered for sale without the ring which I found interesting.
3) I don't know how popular they are but they normally sell for premium over silver melt value. Again, I like them.
4) The Nuevo Peso was introduced in either 1992 or 1993. The most common silver coins I find are the N$10 (see link above). I normally see 1992-1995 dates. Pretty sure the 1996 is very hard to get. Here is something helpful from Wikipedia regarding these coins:
"In 1993, coins of the new currency (dated 1992) were issued in denominations of 5, 10, 20, and 50 centavos and 1, 2, 5, 10, 20, and 50 nuevos pesos. The 5 and 10 centavos were minted in stainless steel, and the 20 and 50 centavos in aluminum bronze. The nuevo peso denominations were bimetallic, with the 1, 2, and 5 nuevos pesos having aluminum bronze centers and stainless steel rings and the 10, 20, and 50 nuevos pesos having .925 silver centers and aluminum bronze rings.
In 1996, the word Nuevo was removed from the coins. New 10 pesos were introduced with base metal replacing the silver center. The 20-, 50-, and 100-peso coins are the only currently circulating coinage in the world to contain any silver."
URL:
https://en.wikipedia.org/wiki/Mexican_peso5) No idea but there were a variety of bimetallic coins struck by their mint. Some may look clad -- bronze ring and Cu-Ni center -- but as I mentioned above, some actually do have silver centers! So dealers that are not familiar with foreign coins may just assume they contain no silver... just a guess.
Hope this helps!
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