i sold my grandfather's coin collection last summer. the buyer flew in from NY. he had no interest in silver/gold certificates, nor confederate money - said they were worth $5/max & the banks no longer recognize them for silver/gold exchange. he advised me to keep them for my son as heritage.
as well, $2 bills, Susan B Anthony's, newer 50-cent & silver dollars, are apparently face value. what they want are the gold & silver coins from 1700-1960, whereas their value is at least twice their weight & more depending on rarity.
if you can afford to keep them & pass them down, do. but remember that one of the best returns now in the Market, is BOGOF at your local grocery store. Ebay is your best source for CMV.