My kids get paper savings bonds from family members for holidays/birthdays/etc. Right now I do nothing with them besides putting them in a fire proof lock box but that can't be the best thing to do. How should I do with paper savings bonds?

My kids get paper savings bonds from family members for holidays/birthdays/etc. Right now I do nothing with them besides putting them in a fire proof lock box but that can't be the best thing to do. What should I do with paper savings bonds?