Silver dollars and stamped 1/10 oz gold bullion cubes do that.
Anything else in times of crisis will have a value that can be disputed. Think what happened when people cashed in grandma's jewelry for melt-down value. They were at the mercy of the person buying it. And gold mutual funds or certificates saying it's being safely stored.....well, that's just plain dumb.
Pre-1965 dimes, quarters and halves are what you want in silver and fractional gold coins. I would not collect bars.