How many coins in that jar (or just how big/full is the jar) and how long has she been accumulating? I haven't found a silver coin in circulation in the last 15 years.

Time might be our friend here, for a pleasant but rare occurrence. Young(er) people weren't around when silver was in circulation and aren't trained to recognize the difference between 90% silver and 25% nickel (clad). So they spend or cash-in grandma's loose change found in the night-stand drawer. Good deal for us eagle eye (with correction ) oldsters.