The best thing I have are 5 percent bonds from 1780,...

The best thing I have are 5 percent bonds from 1780, denominated from $1 to $20. As far as I can tell, they are obligations from the United States of America, so I should be able to walk down to the Federal Reserve and redeem the uncanceled ones. With 217 years of accrued interest, for a $20 bond, that's about $800,000.