Identifying silver non-US coins?

How do I tell if a foreign coin has silver in it? A local antique store has some foreign coins and I was wondering if they had any silver coins in there and didn't know. I noticed some Pesos for example, what year was the last for a silver peso? Is there a site to help with this? The only site I am aware of is coinflation.com, but they only talk about US & Canadian whereas I need help with rest of the world stuff.