When I was a youngin' I could purchase a gallon of gasoline for 2 silver dimes. Todays melt value for two silver dimes according to coinflation.com is approximately $1.16 each, with gas here at $2.36 per gallon today, I can still purchase in a round about way, a gallon of gas for two silver dimes. The very reason to keep some silver and gold IMHO, though I do agree, that you can't eat it.
